The plant ecology of the farm Groothoek , Thabazimbi District . II . Classification

The plant ecology o f the farm G roothoek, Thaba­ zimbi District, was studied in o rder to supply da ta on the Sour Bushveld ( Acocks, 1975) for the natural re­ source classification of the D epartm ent of Agricul­ ture & W ater Supply. This veld type is found mainly in the W aterberg o f the Transvaal and little is known about the vegetation. T he study included classifica­ tion o f the vegetation in term s o f both floristics and structure, as well as correlation of the vegetation classification with the environm ent to facilitate later study o f the entire W aterberg area.

T h e plant ecology o f the farm G roothoek, T haba zim bi D istrict, w as studied in o rd e r to supply d a ta on th e Sour Bushveld ( A cocks, 1975)   T he W aterberg is classified as C w a according to K oppen's classification (Schulze, 1947) although this is not supported by direct evidence as no full climatological station has ever been m aintained in the area.Rainfall statistics indicate th e area as falling under the category Cw, w arm tem p erate with sum m er rainfall, while the high probability th a t the January m ean exceeds 22°C indicates the C w a classi fication (Schulze, 1947).Rainfall records for th e tenyear period July 1963 to June 1973 o n the upper pla teau suggest a mean annual rainfall o f 680 mm.T he consensus o f local opinion, how ever, is th at this period was unusually dry,

M E T H O D S
T he B raun-Blanquet m ethod o f sam pling and syn thesis followed in the study is described by W esthoff & V an d e r M aarel (1973), M ueller-D om bois & Ellenberg (1974) andW erger (1974).
T he study area was stratified into physiognomicphysiographic units determ ined by interpretation o f 1: 33 000 aerial photographs.Sam pling sites w ere lo cated by m eans o f random co-ordinates within each physiognom ic-physiographic unit.This procedure is accom m odated within the flexible B raun-B lanquet m ethod (C oetzee, 1975).170 q u ad rats, 10 x 20 m , w ere sited in hom ogeneous stands representing the different physiognom ic-physiographic units.T he 10 m x 20 m quadrat size used is considered adequate for bushveld vegetation (C oetzee et a /., 1976;Van d e r M eulen, 1979).

D E SC R IP T IO N O F T H E P L A N T C O M M U N IT IE S
In th e community descriptions woody and h erb a ceous species are both listed in o rd e r o f constancy followed by mean percentage cover, with th e re spective values indicated next to each species.Species characteristics o f each com m unity are o m itted from the descriptions because they are d i rectly apparent from T able 2.

A . Kloof forest communities on moderately deep soils in moist sheltered habitats
T h e kloof forest com m unities are found in kloofs in th e east (Com m unities 1 & 3) and in th e west (Com m unity 2) o f the study area (Fig. 3) at altitudes o f 1 050 m to 1 850 m (Table 2).T he vegetation is represented by three com m unities, nam ely C om m unities I to 3 (Tables 2 & 3).

Habitat
T he soils are mainly o f the M ispah Form , M ispah Series, and Shortlands F orm , Bokuil Series, derived from sandstone and diabase respectively.T he soil d epth varies from 140 mm to 470 mm, T he kloofs are the least exposed o f the landform classes (A ppendix A ) found in the study area and as a result probably have the narrowest tem perature range and highest humidity o f th e com m unities in the study area.Streamflow in th e kloof com m unities is season?'

Floristics
A lthough the kloof vegetation is physiognomically hom ogeneous, the com m unities have few species in com m on, viz th e species o f the Diospyros whyteana species-group (Table 2F).T he Olea europaea In th e phytosociological classification, the kloof forest com m unities arc classified as follows (Tables 1,2*3)

E rythrina lysistemon -Celtis africana K loof For est
This forest is found below 1 101 m in a d eep kloof in the south-east o f the study area (Fig. 3).It is rep resented by relev és9 8 an d 100 with 17 and 21 species p e r relevé respectively.This forest com m unity (E d w ards, 1983) has an rL structure (Ito , 1979;Fig. 4a) w ith th e greatest average cover o f 65% in the upper height classes higher than eight m etres.T he kloof is subjected to cold air drainage (C o etzee, 1975) and being situated lower than the o th e r tw o kloof forest com m unities, is not only cooler a t night but can probably reach higher day tem peratures resulting in a greater tem perature range than th e o th e r kioof for est com m unities in the study area.

H abitat
T h e soils are o f the Mispah Form , M ispah Series, derived from sandstone o f the A lm a Grayw acke Form ation.T he average soil dep th varies from 190 mm to 450 mm and the surface rock cover averages 60% .T he kloof slopes from 3° to 6° in a south to south-w est direction.T he electrical resistance o f the soil is the highest in relation to the o th e r kloof com m unities and the T-value is the lowest (T able 2), in dicating nutrient-poor soils.This m ay be attributed to the low altitude with consequent greater stream flow than the high-lying kloofs.T he nutrient-poor soils may also be attributed to periodic flooding as the quadrats w ere placed below the observable floodline w hen sampling.T he soils are strongly acid (M acV icar et al., 1977) with a pH o f 4,8 w hen satu rated with w ater.

Floristics
T he com m unity is diagnosed by the Plectranthus verticillatus species-group (T able 2A ).T he species diversity per unit area is low for the study area with an average o f 4 spccies/mr fo r this com m unity.

T rees and shrubs
Conspicuous woody species with m ore than 5% m ean cover and occurring in m ore th a n 50% o f the relevés representing this com m unity are: 6%

Osyris lanceolata -Celtis africana K loof Forest
T his forest is found at altitudes o f I 300 m to 1 400 m in B akker's Pass, on the escarpm ent in the west o f th e study area (Fig, 3).It is represented by eight relevés (T able 2) w ith 13 to 23 species per relevé.This forest com m unity (E dw ards, 1983) has an rL struc tu re (Ito , 1979;Fig. 4b) with the greatest average cover o f 50% in the > 5 -8 m height class.T h ere are several non-perennial stream s in the com m unity w hich, in area, is the largest o f the o th e r kloof com m unities (Fig. 3).T h e com m unity is sheltered and is situated at an altitude betw een th at o f the o th er kloof com m unities (T able 2), probably resulting in the narrow est tem perature range and highest hum id ity o f the kloof forest com m unities.

H abitat
T h e soils are o f the Shortlands F orm , Bokuil Se ries, derived from diabase o f the post-W aterberg G roup.T h e average soil dep th varies from 140 mm to 470 mm and th e surface rock cover varies from 15 to 40% .T h e kloof slopes from 3° to 17° in a southerly to westerly direction.T he electrical resistance o f the soil is th e lowest recorded fo r all the com m unities in the study area, w hereas the T-value is am ongst the highest (Table 2 ), indicating nutrient-rich soils.T he soils are m oderately acid (M acV icar et al., 1977) with a pH o f 6,5 when saturated with w ater.

Floristics
T his com m unity is distinguished by the Osyris lan ceolata species-group (Table 2 B ). T h e species diver sity p er unit area is the lowest for the kloof com m unities with an average o f 2,6 species/m-for the < eight relevés.

T rees and shrubs
Conspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing the com m unity are:  2F) is com m on to C om m unities 1 ,2 & 3.The Cyperus albostriatus species-group (Table 2H ) shows affinities with the m ain vegetation type B , but as the affinity is limited to C om m unities 4 & 5 this speciesgroup may be regarded as representing forest-m argin species.
T he com m unity is accessible to grazing in places and the area represented by these releves contain grass patches as forest incursors.

Asplenium splendens -Celtis africana K loof For est
This forest is found a t altitudes o f I 600 m to 1 850 m in tw o kloofs in th e north and north-east o f the study area (Fig. 3) and is represented by six relevés (Table 2) with 13 to 24 species p er relevé.It (E d w ards, 1983) has an rL structure (Ito , 1979;Fig. 4c) w ith the greatest average cover o f o ver 50% in the higher than twelve m etres height class.It is found at the highest altitude for the kloof forest com m unities in the study area and is consequently influenced by mist which occurs frequently o n the K ransberg massif, but because the kloofs are generally shallow the com m unity is m ore exposed than the o th e r kloof com m unities and should, therefore, experience a greater am plitude in tem perature.to 390 mm and th e surface rock cover varies from 40 to 95% .
T h e kloofs slope from 17° to 30° in a southerly to south-easterly direction.T he electrical resistance of th e soil is low a t 2 200 ohm s with a high T-value of 22,0 me/100 g indicating a richer nutrient status than for C om m unity 1.This may be attributed to th e pro tection afforded to the soil, found mostly in pockets betw een boulders, by the large rocks and boulders found in this c o m m i^'ty .T he effect o f stream flow on th e Icaching o f nutrients from the soil should th erefo re be minim ized.F urtherm ore, the stream flow in these two kloofs is considerably less than in th e o th e r kloofs because these tw o kloofs are situ a ted at a high altitude and d o not have feeder stream s.It is also suggested that this com m unity is not subjected to flooding as severe as in the o ther kloof com m unities.T he soils are strongly acid (M ac-V icar et al., 1977) with a pH o f 4,1 when saturated w ith w ater.

Floristics
T he com m unity is differentiated by the Asplenium splendens species-group (T able 2D ).T he species di versity per unit area averages 2.8 species/m-for the six relcves.
T rees and shrubs C onspicuous woody species, with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing this com m unity are: Podocarptts latifolitis (tre e ) 83% 47% Myrsine africana and Diospyros whyteana both oc cur with 100% constancy but with 2,5% and 2,2% m ean cover respectively.Widdringtonia nodiflora occurs w ith 33% constancy and 1,3% cover but also occurs in the grassland C om m unity IS as a forest in itial (E dw ards, 1967).
T he sm aller kloof represented by relevé num ber 113 has a high cover-abundance (11 % -25% ) o f the tree fern Cyathea dregei (Table 2).This sm aller kloof is relatively inaccessible, while the larger kloof is m ore accessible, being the m ost used route to the to p o f Kransberg.T here a re , how ever, isolated stum ps o f Cyathea dregei in the larger kloof, suggest ing that the habitat is suitable for grow th o f the tree fern.It is suggested, therefore, that were it not for the rem oval o f Cyathea dregei this species would be a character species for Com m unity 3 with a high cove r-abu nd a nee.2E ) and the Diospyros why tea na species-group (T able 2F) is com m on to the three kloof forest com m unities.T he Cyperus albostriatus species-group (Table 2H ) shows affinities with the m ain vegetation type B but only as regards forest-m argin species.Com m unity 3 is sim ilar to C om m unity 2 in respect o f com m on species-groups, how ever, unlike C om m unity 2, C om m unity 3 does not have the Olea europaea species-group (Table 2C) in com m on with C om m unity 1.This difference may be attributed to the higher altitude in which C om m unity 3 occurs indicating th at the Olea eu- T he w oodland com m unities representing A cocks's (1975) Sour Bushveld are found south o f the Kransberg massif in the study area (Fig. 3) below I 600 m altitude.

Habitat
T he soils are mainly o f the M ispah Form (M ispah Series) with the H utton Form (M iddelburg Series), Shortlands Form (Bokuil Series) and the W cstleigh Form (Sibasa Series) also occurring.Soil dep th va ries from 40 mm to m ore than t 000 m m with 57% of the soil depths recorded being g reater than 130 mm.T he com m unities are m ore exposed than the kloof com m unities, but m ore sheltered than the com m uni ties o n th e u p p er slopes o f the K ransberg massif and on the up p er sum m it (Fig. 2), being sheltered by the K ransberg massif.

Floristics
T he vegetation is structurally heterogeneous, va rying from closed w oodland to open w oodland and occasionally sparse w oodland (Table 2).T he Combretum molle species-group (Table 2 A

Coleochloa setifera -Combreium molle
O p e n W oodland 11. p er relevé.T his closed-w oodland com m unity (E d w ards, 1983) has a D structure (Ito , 1979;Fig, 4d) w ith th e greatest average cover o f about 27% in the > 3 m -5 m height class.B ecause the slopes o n which this com m unity is found are south facing, the tem p eratu re is likely to be low er than that o f the northfacing slopes (T h ero n , 1973) and if night tem p era tures arc eq u al, should have a sm aller tem perature range th an th at o f the north-facing slopes.

Habitat
T he soils are o f the M ispah Form , M ispah Series, derived from sandstone o f th e A asvoëlkop F o rm a tion.T h e average soil dep th varies from 150 mm to 500 m m a n d th e surface rock cover varies from 1% to 40% .T h e terrain slopes from 3° to 25° in a so u th erly d irectio n .T h e electrical resistance o f the soil is 4 700 ohm s and the T-value is 8,5 me/100 g w hich is m oderate fo r th e study area indicating a m oderate nutrient status.A s the com m unity is situated o n the lower slopes, nu trient accum ulation from run-off is g reater th a n fo r the upper slopes (R ussell, 1961), w here g re ater leaching can be expected.T he soils are strongly acid (M acV icar et al., 1977) w ith a pH of 4,8 when saturated with w ater.

Floristics
T his com m unity is differentiated by the Achvranthes aspera species-group (Table 2G ).T he species diversity p er unit area averages 5,8 species/m 2 fo r the C om m unity.T he character species for th e species-group are mainly pioneer forbs, which could have a w ider presence than th at indi cated o n T ab le 2. H ow ever, at the tim e o f sam pling they w ere characteristic o f Com m unity 4 in th e study area and a re , th erefore, classified accordingly.

T rees and shrubs
C onspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing this com m unity are: Combreium molle (tree/shrub) 90%

5,1%
Faurea saligna (tree /sh ru b ) 60% 6,2% H erbs H erb species occurring in m ore than 50% o f the relevés rep resen ting the Com m unity are:  2G ) w ere pos sibly elim inated by reduced grazing pressure, then this com m unity w ould be floristically m ore sim ilar to C om m unity 5 than is indicated o n T able 2.

Euclea crispa -C om bretum m olle Closed Wood land
T his w oodland is found at altitudes o f 1 500 m to 1 550 m o n the lower slopes o f the K ransberg massif in th e north o f the study area (Fig. 3).It is re p resen t ed by relevês 145, 153 and 134 with 25, 30 and 34 species p er relevé respectively.T his closed-woodland com m unity (E dw ards, 1983) has a D structure (Ito , 1979;  T he soils a re strongly acid (M acV icar et al., 1977) with a pH o f 4,8 when saturated with w ater.

Floristics
T he com m unity is differentiated by the absence o f ch aracter species, as well as the absence o f the Achyranthes aspera species-group (T able 2G ), and the presence o f the Aristida aequiglumis species-group (Table 2 0 ) and the Cyperus albostriatus speciesgroup (T able 2H ).T he species diversity p er unit area averages 4,7 species/m 3 for th e C om m unity which is less than fo r C om m unity 4 , possibly as a r e sult o f the high surface rock cover in C om m unity 5 w ith 1 consequently less soil area for vegetation as well as few er annual and pioneer species.

T rees and shrubs
C onspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing the C om m unity are:     (Ito , 1979;Fig. 4f) with th e greatest average cover o f ab o u t 22% in the > 3 m -5 m height class.A lthough this com m unity is situated in a kloof, the kloof is very broad and shal low so th at th e vegetation is m ore exposed with a consequently g re ater tem perature range and is less moist than the kloof forest com m unities.T h e vege tation is, therefore, a closed w oodland and not a for est as could be expected from the landform class H (T able 2).

Florist ics
This com m unity is differentiated by the Setaria megaphylla species-group (T able 21).Setaria mega phylla is also found in C om m unity 1 with 100% con stancy but with a lower m ean percentage cover (Table 2).T h e species diversity p er unit area aver ages 5,3 species/m J for the com m unity.

T rees and Shrubs
T h e only conspicuous w oody species with m ore than 5% m ean cover and occurring in m ore than 50% o f th e relevés representing the com m unity is: H erbs H erb species occurring in m ore than 50% o f the relevés representing the com m unity are:

T erm inalia sericea -C om bretum m olle Closed Woodland
This w oodland is found at altitudes o f 1 415 m to 1 425 m in the eastern central part o f the study area o n the upper plateau (Fig. 3).It is represented by relevés 79, 80 and 77 with 30, 30 and 22 species per relevé respectively.T his closed-w oodland com munity (E dw ards, 1983) has an rL structure (Ito , 1979;Fig. 4g) with the greatest average cover o f about 37% in the upper height class o f > 5 m -8 m.T he com m unity is probably subjected to tem p era tu re inversion at night because it is situated n e a r a stream in a depression.T he tem perature range should, therefore, be w ide for the study area.

H abitat
T he soils are o f the H utton Form , M iddelburg Se ries, derived from conglom erate o f the A lm a G ray w acke Form ation.T he average soil dep th varies from 150 m m to 650 mm and the surface rock cover varies from 1% to 2% .T h e terrain slopes from 1° to 2° in a northerly direction.T he electrical resistance o f the soil is 6 400 ohm s and th e T-value is 5,9 me/100 g indicating a poor nutrient status for the soils, which may be attributed to leaching.T h e soils are strongly acid (M acVicar et al., 1977) with a p H o f 4,1 w hen saturated with w ater.

Floristics
T he com m unity is distinguished by th e Terminalia sericea species-group (T able 2J).T he species diver sity per unit area averages 7 species/m ! for the com m unity which is relatively high for the study area.

T rees and shrubs
Conspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing the com m unity are:

A ristida diffusa -C om bretum m olle Open Woodland
This w oodland is found a t altitudes o f 1 250 m to 1 400 m on the lower slopes o f the low er plateau in the south o f th e study area with an o u tlie r o f the com m unity above the eastern kloof on the upper plateau (Fig. 3).This com m unity is differentiated by the Aristida diffusa species-group (Table 2K ) which only has o ne character species, nam ely Aristida dif fusa.T he com m unity is separated into th e following two variations, based on floristics:

Strychnos m adagascariensis -A ristida diffusa -C om bretum m olle Variation
This variation is found at altitudes o f 1 250 m to 1 325 m , being th e lowest altitude o f the com m uni ties on th e lower plateau in the south o f th e study area (Fig. 3).It is represented by six relevés w ith 23 to 38 species p e r relevé.This open-w oodland varia tion (E dw ards, 1983) has an L structure (Ito , 1979;Fig. 4h) with th e greatest average cover of about 20 per cent in th e lowest height class o f 0,0 m -0,5 m .T he low er plateau is exposed and a wide tem p era ture range could be expected, while the open vegeta tion indicates a low m oisture status for this variatio n .

H abitat
T he soils are o f the M ispah Form , M ispah Series, derived from sandstone o f the Alm a Grayw acke Form ation.T h e average soil depth varies from 120 mm to 170 mm and the surface rock cover varies from 50% to 70% .T he terrain slopes from 1° to 9° in a southerly to south-w esterly direction.T he electri cal resistance o f the soil is 3 500 ohm s and the T-val ue is 7,1 me/100 g indicating a m oderate nutrient status.T he soils are strongly acid (M acV icar et al., 1977) with a pH o f 5,4 w hen saturated with w ater.

Floristics
This variation is distinguished by the Schrebera alata species-group (Table 2L).T he species diversity per unit area averages 5,5 species/m 2 fo r the V aria tion.

T rees and shrubs
Conspicuous woody species with a 2,5% o r m ore m ean cover and occurring in m ore than 50% o f th e relevés representing this variation are: T his variation is found at altitudes o f 1 325 m to 1 400 m upslope o f variation 8.1 on th e low er pla teau in the south o f the study area and o n the slopes leading to a kloof on the upper plateau in the east of the study area (Fig. 3).It is rep resen ted by six relevés with 20 to 30 species p er relevé.This openw oodland V ariation (E dw ards, 1983) h as an L struc ture (Ito , 1979;Fig. 4i) w ith th e greatest average cover o f 25% in the lowest height class o f 0,0 m -0,5 m , which is greater than that fo r V ariation 8.1.T h e 5,0% 2,2% 0, 2%

Habitat
T h e soils are o f the M ispah Form , M ispah Series, derived from sandstone in the ease o f relevés 8 6 ,8 9 , 90, 87 and 96 and conglom erate in the case o f reievé 104, b oth o f th e Alm a G rayw aeke F orm ation.T he average soil depth varies from 100 mm to 190 mm and th e surface rock cover varies from 60% to 70% .T he terrain slopes up to 28° in a southerly to south easterly direction in the case o f relevés 86, 8 9 ,9 0 ,8 7 and 96 and in a northerly direction in the case o f relevé 104.T h e electrical resistance varies from 3 500 ohm s to 6 700 ohm s and the T-value varies from 7,1 me/100 g to 10,5 me/100 g, indicating soils o f a m od erate nutrient status.T he soils are strongly acid (M acVicar et al., 1977) w ith a pH range o f 4,5 to 5,4 when satu rated with w ater.
T h e difference in the soil factors found in this va riation may be attributed to the difference in parent m aterials in th e case o f relevé 104 and possibly to the leaching effect o f a seasonal stream which causes periodic flooding in the vicinity o f relevé 96, with increased runoff and consequent leaching.

Floristics
This variation is differentiated by the absence of character species and notably the absence o f the species o f th e Schrebera alata species-group (Table 2L) which differentiates this variation from the Strychnos madagascariensis -Aristida diffusa -Com bretum molle V ariation.T he species diversity per unit area averages 4,8 species/m 2 for this variation which is low er th an for V ariation 8.1.

T rees and shrubs
Conspicuous woody species with 2,5% o r m ore m ean cover and occurring in m ore than 50% o f the relevés representing the variation are: Diplorhynchus condylocarpon (tree /sh ru b ) 83%
H erbs H erb species occurring in m ore than relevés representing the variation are; G eneral V ariation 8.2 has the sam e affinities with o ther com m unities as that described for V ariation 8.1

Closed Woodland
This w oodland is found a t altitudes o f 1 425 m to 1 550 m south o f the upper plateau in the southern half o f th e study area (Fig, 3).T he com m unity is di agnosed by th e Landolphia capensis species-group (Table 2M ).
This com m unity is differentiated into the follow ing two variations, based on floristics:

Burkea africana -Landolphia capensis -
Combretum molle V ariation found on soils w ith a m oderate surface rock cover, 9.2 Tapiphyllum parvifotium -Landolphia capen sis -Combretum molle V ariation found on soils with a m oderate to high surface rock cover.

B urkea africana -* Landolphia capensis -Com bretum m olle Variation
This variation is found at altitudes o f 1 425 m to 1 550 m south o f th e upper plateau in the southern half o f the study area (Fig. 3).It is represented by eight relevés with 19 to 31 species per relevé.This closed-woodland variation (E dw ards, 1983) has a D structure (Ito , 1979;Fig. 4 j) with the greatest aver age cover o f 15% in the > 3 m -5 m height class.
T h e variation occurs on north-facing slopes (T heron, 1973) and should therefore have a greater tem pera ture range than the south-facing slopes, if night tem peratures are the sam e.

H abitat
The soils are o f the M ispah Form , M ispah Series, derived from conglom erate o f the A lm a Grayw aeke Form ation.T he average soil depth varies from 40 mm to 250 m m and the surface rock cover varies from 5% to 25% .T he terrain slopes up to 6° in a northerly to easterly direction.T he electrical resist ance is 6 700 ohm s and the T-value is 10,5 me/100 g indicating soils o f a m oderate nutrient status for the study area.T h e soils are strongly acid (M acV icar et al., 1977) with a pH o f 4,5 w hen saturated with water.

Floristics
T he V ariation is differentiated by the absence o f character species as well as the absence o f the Selaginella dregei species-group (Table 2P) which differen tiates this variation from the Tapiphyllum parvifolium -Landolphia capensis -Combretum molle Va riation.T he species diversity per unit a re a averages 5 species/m2 for the variation.

T rees and Shrubs
Conspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing the variation are: Ochna pulchra (tree /sh ru b ) 88% 7,6% Burkea africana has the highest constancy value in the study area in V ariation 9.1.

Herbs
H erb species occurring in m ore than 50 p er cent of the relevés representing the variation are:   This variation is found at altitudes 1 425 m to 1 525 m south o f th e upper plateau in the southern half o f th e study a re a (Fig. 3).It is represented by twelve relevés with 21 to 34 species p er relevé.This closed-w oodland variation (Edw ards, 1983) has a D structure (Ito , 1979;Fig. 4k) with the greatest aver age cover o f 10% in the > 3 m -5 m height class.This variation can, therefore, be considered to be m ore op en than V ariation 9.1 which could indicate a drier m oisture regim e than for V ariation 9.1.T he tem perature regim e should be sim ilar to that o f V a riation 9.1.

Habitat
T h e soils are o f the Mispah Form , M ispah Series, derived from conglom erate o f the Alma G rayw aeke Form ation.T h e average soil depth varies from 50 mm to 230 m m and the surface rock cover varies from 5% to 80% .T he terrain slopes from 1° to 8° in a north-easterly direction.T he electrical resistance o f the soil is 6 700 ohm s and the T-value is 10,5 me/100 g indicating a m oderate nutrient status for the study area.T he soils a re strongly acid (M acV icar et al., 1977) with a pH o f 4,5 when saturated with water.

Floristics
T his variation is differentiated by the absence o f character species and is differentiated from the Bur kea africana -Landolphia capensis -Combretum molle V ariation by the presence o f the Selaginella dregei species-group (Table 2P).T he species diver sity p er unit area averages 4,4 species/m-for this va riation, which is low er than for V ariation 9.1.

T rees and shrubs
T h e only conspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f th e relevés representing the variation is: Burkea africana (tree /sh ru b ) 67%

7,35%
Combretum molle has a 100% constancy in V aria tion 9.2, b u t only 4,4% m ean cover, w hereas Ochna pulchra has 83% constancy and only 4,1% mean cover indicating the lesser cover o f these tw o species in this variation com pared with V ariation 9.1.

75%
Andropogon schirensis (grass I 67% Indigofera egens (fo rb ) 67% G eneral Com m unities 8 to 9 ,5 to !1 and 8 to 16 are related to each o th er through the shared presence o f the Di plorhynchus condylocarpon species-group (Table 2N ), the Aristida aequiglumis species-group (Table 2Q ) and the Schizachyrium sanguineum speciesgroup (Table 2W ) respectively which corresponds to that for the Burkea africana -Landolphia capensis -Combretum molle V ariation, T he Selaginella dregei species-group (Table 2P) is com m on to Com munity 10 and V ariation 9.2, but is absent in V ariation 9.1.
Selaginella dregei has a 75% constancy which is high fo r the study area and is indicative o f the high su r face rock cover for V ariation 9.2 because Selaginella dregei only occurs w here th ere are sheet outcrops.
T he high surface rock cover is a possible reason for the structural differences betw een the two variations o f Com m unity 9 and can also contribute to the flor istic differences betw een the tw o variations.

C oleochloa setifera -C om bretum m olle Open Woodland
T his w oodland is found at altitudes o f 1 525 m to 1 550 m south o f the upper plateau in the southern half o f the study area (Fig. 3).It is represented by eight relevés with 26 to 33 species p e r relevé.This open-w oodland com m unity (E dw ards, 1983) has an L structure (Ito, 1979;

Habitat
T he soils are o f the M ispah F orm , M ispah Series, derived from conglom erate o f the Alm a Grayw aeke F orm ation.T h e average soil d epth varies from 40 mm to 80 mm and the surface rock cover varies from 60% to 80% .T he terrain slopes from 18° to 25° in a southerly direction.T he electrical resistance is 6 700 ohm s and the T-value is 10,5 me/100 g indicating soils o f a m oderate nutrient status for the study area.
T he soils are strongly acid (M acV icar et al., 1977) with a pH o f 4,5 when saturated with w ater.

Floristics
T he com m unity is distinguished by the Coleochloa setifera species-group (Table 2 0 ) .T he species diver sity p e r unit area averages 5,3 species/m-for the com m unity.

T rees and shrubs
T he only conspicuous woody species w ith 2,5% o r m ore m ean cover and occurring in m ore than 50% of the relevés representing the com m unity is: 1,1%

Closed and Open Woodlands
T hese woodlands are found a t altitudes o f 1 400 m to 1 600 m in th e north, south-east and south-w est of th e study area (Fig. 3).This com m unity is differen tiated by the absence o f character species as well as th e absence o f the Cyperus albostriatus speciesgroup (Table 2 H ), the Setaria megaphylla speciesgroup (T able 21), the Terminalia sericea speciesgroup (T able 2J), the Diplorhynchus condylocarpon species-group (T able 2N ), the Selaginella dregei species-group (Table 2P ), the Stoebe vulgaris species g roup (T able 2U ) and the Senecio erubescens species-group (Table 2V) in the main vegetation type B, as well as the presence o f the Aristida ae quiglumis species-group (T able 2 0 ) .This com m unity is separated into the following tw o varia tions, based o n floristics: This variation is found at altitudes o f 1 400 m to 1 575 m o n the lower slopes o f the K ransberg massif in the north as well as in the south-w est and south east o f the study area (Fig. 3).It is represen ted by ten relevés with 19 to 32 species per relevé.This closed-woodland variation (E dw ards, 1983) has a D structure (Ito , 1979;Fig. 4m ) with the greatest aver age cover o f 20% in the > 3 m -5 m height class.
Because the variation has a closed-w oodland struc tu re, the tem perature range is likely to have a nar row er am plitude and the m oisture regim e is likely to be higher than for V ariation 11.2.

Habitat
T he soils are o f the Mispah F orm , M ispah Series, derived from sandstone o f the A asvoëlkop Form a tion, in the case o f relevés 154,151,143,139,146,147 and 24, and conglom erate o f the Alm a Graywacke Form ation in the case o f relevés 59, 49 and 50.T h e average soil depth varies from 40 mm to 230 mm and th e surface rock cover varies from 20% to 60% .T he terrain slopes up to 25° in a southerly di rection.T he electrical resistance o f th e soils varies from 2 100 ohm s to 6 700 ohm s.T he T-value varies from 7,4 me/100 g to 15,8 me/100 g indicating soils of a predom inantly high nutrient status.T he soils are strongly acid (M acV icar etal., 1977) with a pH o f 4,1 to 4,5 except for relevé 24 which has a pH o f 6,0 w hen saturated with w ater and is, th erefo re, m oder ately acid.T he habitat factors for this variation have a wide range which may be attributed to th e distribu tion o f this variation which occurs as small areas, widely dispersed through the study area (Fig. 3).

Floristics
This variation is differentiated by the absence o f character species as well as the absence o f the Helichrysum sp.species-group (T able 2 A B ), which distinguishes it from the Chaetacanthus costatus -Heteropogon contortus -Combretum molle V aria tion.T h e species diversity p er unit area averages 4,8 species/m 2 fo r this variation.

T rees and shrubs
T he only conspicuous woody species with m ore than 5% m ean cover and occurring in m ore than 50% o f the relevés representing this variation is: Burkea africana (tree/sh ru b ) 70% 13% Rhus dentata (shrub) occurs in 70% o f the relevés and has a m ean cover o f 1,4% .

General
Communities 5 to 11 are related to each other through the shared presence of the Aristida diffusa species-group (Table 2 0 ) and Communities 8 to 16 are related to each other through the shared pre sence o f the Schizachyrium sanguineum speciesgroup (Table 2W).

Chaetacanthus costatus -Heteropogon contortus -Combretum molle Open Woodland Varia tion
This variation is found at altitudes of 1 500 m to 1 600 m on the lower slopes of the Kransberg massif in the northern half o f the study area (Fig. 3).It is represented by eight relevés with 20 to 27 species per relevé.This open-woodland variation (Edwards, 1983) has an L structure (Ito, 1979;Fig. 4n) with the greatest cover of 25% in the 0,0 m-0,5 m height class.Because the Variation is generally situated upslope of Variation 11.1, it is probably more exposed with a consequently greater tem perature amplitude and a drier moisture regime than Variation 11.1.

Habitat
The soils are of the Mispah Form, Mispah Series, derived from sandstone o f the Aasvoélkop Form a tion.The average soil depth varies from 110 mm to 210 mm and the surface rock cover varies from 15% to 60% .The terrain slopes from 3° to 21° in a south erly direction.The electrical resistance is 4 400 ohms to 5 100 ohms for the soils and the T-value varies from 6,3 me/100 g to 8,5 me/100 g which is generally lower than that for Variation 11,1 indicating soils of a lower nutrient status, This may be as a result of Variation 11.2 being generally upslope of Variation 11.1 with nutrients lost by runoff from Variation 11.2 to 11.1.The soils are strongly acid (MacVicar et al., 1977) with a pH range of 4,3 to 4,8 when satu rated with water.

Floristics
This variation is marked by the absence of charac ter species and is distinguished from Variation 11.1 in Community 11 by the presence of the Helichrysum sp.(Westfall 921) species-group (Table 2AB).The species diversity per unit area averages 5,4 species/m' for this variation which is higher than that for Variation 11.1.

Trees and shrubs
Conspicuous woody species with 2,5% or more mean cover and occurring in more than 50% o f the relevés representing the variation are: Combretum molle (tree/shrub) 88%

General
Communities 5 to 11 and 8 to 16 are related to each other through the shared presence o f the Aris tida aequiglumis species-group (Table 2 0 ) and the Schizachyrium sanguineum spccies-group (Table 2W) respectively.Variation 11.2 and Communities 12, 17 and 18 are related to each other through the shared presence of the Helichrysum species-group (Table 2AB).

Themeda triandra -Combretum molle Open Woodland
This woodland is found at altitudes of 1 400 m to 1 600 m in the south, north and west of the study area (Fig. 3).It is represented by thirteen relevés with 21 to 29 specics per relevé. This open-woodland community (Edwards, 1983) has an L structure (Ito, 1979;Fig. 4o) with the greatest average cover of 38% in the 0,0 m-0,5 m height class.The tem pera ture range should be wide and the moisture regime should be dry, because of the relatively exposed situ ation o f this community.

Habitat
The soils are mainly of the Mispah Form , Mispah Series, derived from sandstone o f Aasvoëlkop and Alma Graywaeke Formations and shale o f the Aasvoëlkop Formation, Soils o f Shortlands Form, Bo kuil Series, derived from diabase of the post-Waterberg Group, are also found in this community (relevés 165 and 164).The class limits set for the soil classification used in this study (MacVicar et al., 1977) are not necessarily the same as the limits influ encing the vegetation (D.Edwards, pers.comm.), hencc the variation of soil within this community.The Shortlands Form recorded for this community can, furthermore, be regarded as atypical because of the shallow soil depth of 80 mm recorded (Table 2).The average soil depth varies from 80 mm to 300 mm and the surface rock cover varies from 5% to 60% .The terrain slopes from 3° to 24° in a south-easterly to westerly direction.The electrical resistance of the soils varies from 3 200 ohms to 6 000 ohms and the T-value varies from 4,4 me/100 g to 7,4 me/100 g, indicating soils with a moderate nutrient status.The soils are strongly acid (MacVicar et a t., 1977) with a pH range of 4,5 to 5,0 when saturated with water.

Floristics
The Community is diagnosed by the absence of character species as well as the absence of the Art's-tida aequiglumis species-group (Table 2Q) and the Senecio erubescens species-group (Table 2V) and the presence of the Helichrysum sp.species-group (Table 2AB) in the main vegetation type B, distin guished by the Combretum molle species-group (Table 2AC).The species diversity per unit area av erages 5,8 species/m2 for this community.

Trees and shrubs
Conspicuous woody species with 2,5% o r more mean cover and occurring in 50% of the relevés rep resenting this community are: Faurea saligna (tre e /sh n ib ) 62% 3,4% Faurea saligna occurs in eleven of the twelve com munities of the main vegetation type B represented by species-group AC (Table 2), but has the highest mean percentage cover of its range in the study area in Community 12.

Herbs
Herb species occurring in more than 50% of the relevés representing this community are;  2W) and Variation 11.2 and Communities 12, 17 and 18 are related to each other through the shared presence of the Helichrysum sp.species-group (Table 2AB).

Argyrolobium transvaalense -Combretum molle Open Woodland
This woodland is found at altitudes of 1 435 m to 1 575 m on the lower slopes of the Kransberg massif in the north-west of the study area (Fig. 3).It is rep resented by five relevés with 22 to 31 species per re- levé. This open-woodland community (Edwards, 1983) has an L structure (Ito, 1979;Fig. 4p) with the greatest average cover o f 20% in the 0,0 m -0,5 m height class.This community is more exposed, as a result of its situation on prominent ridges, than the other communities of the lower slopes and large tem perature fluctuations and a dry moisture regime can consequently be expected.

Habitat
The soils are of the Mispah Form , Mispah Series, derived from sandstone of the Aasvoëlkop Forma tion.The average soil depth varies from 120 mm to 150 mm and the surface rock cover varies from 7% to 15%.The terrain slopes up to 27° in a south-east erly to south-westerly direction.The electrical resist ance of the soils is 2 100 ohms indicating a moderate nutrient status.The soils are moderately acid (Mac Vicar et al., 1977) with a pH of 6,0 when saturated with water.

Floristics
This community is distinguished by the Vernonia oligocephala species-group (Table 2R).The species diversity per unit area averages 7,8 species/m-for this community which is relatively high for the study area.

Trees and shrubs
There are no woody species with a mean cover of 2,5% or more.Woody species occurring in more than 50% o f the relevés representing this community are; Argyrolobium transvaalense (shrub) 100% Faurea saligna (tree /sh ru b )

Herbs
Herb species occurring in more than 50% of the relevés representing this community, are;

General
Communities 13 to 16 are related to each other through the shared presence of the Senecio erubes cens species-group (Table 2V) and Communities 8 to 16 are related to each other through the shared pres ence of the Schizachyrium sanguineum speciesgroup (Table 2W).

Pachycarpus schinzianus -Combretum molle Open Woodland
This woodland is found at altitudes 1 425 m to 1 465 m on the upper plateau and adjacent southfacing lower slopes in the centre of the study area 1 , 1 % (Fig. 3).It is represented by six relevés with 24 to 2? species per relevé. This open-woodland variation (Edwards, 1983) has an L structure (Ito, 1979;Fig. 4q) with the greatest average cover of 10% in the 0,0 m-0,5 m height class.Being situated adjacent to the upper plateau, probably subjected to marked tem perature inversion at night, this community can be expected to have a wide tem perature range and rela tively dry moisture status.

Habitat
The soils arc mainly of the Mispah Form , Mispah Series, derived from sandstone of the Aasvoëlkop Formation but relevés 22 and 23 represent soils of the Westleigh Form, Sibasa Series, also derived from sandstone of the Aasvoëlkop Formation.The soils of the Westleigh Form appear in isolated pock ets and are not large in extent, resulting in no appar ent vegetation change at the scale of this study.The average soil depth varies from 80 mm to deeper than 1 000 mm and the surface rock cover is 4% o r less.The terrain slopes up to 5° in a southerly direction with one relevé (17) representing a 2° slope in a northerly direction.The electrical resistance of the soils is 2 100 ohms to 2 800 ohms and the T-value varies from 3,4 me/100 g to 9,3 me/100 g indicating a moderate nutrient status for the Mispah Form soils and a low nutrient status for the Westleigh Form soils.T he soils are moderately acid (MacVicar et al., 1977) with a pH o f 6,0 when saturated with water.

Floristics
This community is distinguished by the Pachycarpus schinzianus species-group (Table 2S).The species diversity per unit area averages 7,3 species/ m^for the Community.

Trees and shrubs
The only conspicuous woody species with 2 ,5 % or more mean cover and occurring in 50% of the relevés representing this community is: Hypericum aethiopicum (forb) 67% 0,03%

General
Communities 13 to 16 are related to each other through the shared presence of the Senecio erubescens species-group (Table 2V) and Communities 8 to 16 are related to each other through the shared pres ence of the Schizachyrium sanguineum speciesgroup (Table 2W).

15.
Protea caffra -Com bretum molle Open Woodland This woodland is found at altitudes of 1 425 m to 1 575 m on the upper plateau and the adjacent south-facing lower slopes in the northern half of the study area (Fig. 3).It is represented by eight relevés with 18 to 30 species per relevé. This open-woodland community (Edwards, 1983) has an L structure (Ito, 1979;Fig. 4r) with the greatest cover of 20% in the 0,0m-0,5 m height class.Being situated adjacent to the upper plateau, this community can be expected to have a wide tem perature range and dry moisture status.

Habitat
The soils are mainly of the Mispah Form , Mispah Series, derived mainly from sandstone of the Aasvoelkop Formation but also conglom erate, in the case of relevé 78, of the Alma Graywaeke Forma tion.Relevé 14 represents soils o f the Westleigh Form , Sibasa Series, derived from sandstone of the Aasvoëlkop Formation.The average soil depth va ries from 80 mm to deeper than 1 000 mm and the surface rock cover varies from 1% to 15%.The ter rain slopes from 1° to 19° in a south to south-easterly direction with relevé 78 on the upper plateau rep resenting a slope of 2° in a northerly direction.The electrical resistance of the soils varies from 2 100 ohms to 4 700 ohms and the T-value varies from 3,4 me/lOOg to 9,3 me/100 g, indicating soils with a low to moderate nutrient status.The soils are moder ately to strongly acid (MacVicar et al., 1977) with a pH range of 5,0 to 6,0, when saturated with water.

Floristics
This community is distinguished by the absence of character species and the absence of the Vernonia oligocephala species-group (Table 2R ), the Pachycarpus schinzianus species-group (Table 2S) and the Cyperus denudatus species-group (Table 2T) to gether with the presence of the Senecio erubescens species-group (Table 2V).The species diversity per unit area averages 6,5 species/m2 for this com munity.

Trees and shrubs
All woody species have less than 2,5% mean cover.Woody species occurring in more than 50% of the relevês representing this community are:  The grassland phase of Acocks's (1975) Sour Bushveld is represented by one community in the study area, viz the Eragrostis pallens -Andropogon appendiculatus Grassland.

Eragrostis pallens -Andropogon appendicula tus Grassland
This grassland is found at altitudes o f I 400 m to 1 465 m on the upper plateau (Fig. 7) in the central part of the study area (Fig. 3).It is represented by twelve relevés with 12 to 28 species per relevé.This grassland community (Edwards, 1983) has an L structure (Ito, 1979;Fig. 4s) with the greatest aver age cover of 23% in the 0,0 m-0,5 m height class.However, relevé 1 represents vegetation classified as dwarf shrubland (Edwards, 1983) because of the presence, of Stoebe vulgaris which has a mean cover of 42% in this relevé (Fig. 8).T he upper plateau is possibly subjected to tem perature inversion at night because of the slopes to the north and south, result ing in wide tem perature fluctuations.Except for the rainy season, when the water table is high or at the soil surface for large areas of the upper plateau, this community is very dry, possibly because o f the ex posed nature o f the habitat and lack of high vegeta tion cover,

Habitat
The soils are mainly of the Mispah Form, Mispah Series, derived from shale of the Aasvoelkop For mation and the Kroonstad Form, Sibasa Series, de rived from shale of the Aasvoelkop Formation and conglomerate of the Alma Graywacke Formation.The average soil depth varies from 150 mm to deeper than 1 000 mm but the impermeable shale causes a high water table, varying from 150 mm to deeper than 1 000 mm at the time of sampling, that could have a limiting effect on maximum root deplh.
No surface rocks were recorded for this community.
The terrain slopes up to 3° mainly in a south-easterly to south-westerly direction but also northerly in the case of relevé 8.The electrical resistance varies from 3 100 ohms to 4 800 ohms and the T-value varies from 5,9 me/100 g 11,8 me/100 g indicating soils of a predominantly high nutrient status, possibly owing to cation adsorption by the clay fraction derived from the shale.The soils are strongly acid (MacVicar et al., 1977) with a pH of 4,5 to 4,7 when saturated with water.

Floristics
The community is diagnosed by the Cyperus dentidatus species-group (Table 2T).The species diver sity per unit area averages 6,1 species/m -for the Community.

Trees and shrubs
Only an isolated Protea caffra tree was recorded for this community.The dwarf shrub Stoebe vulgaris with a constancy of 53% has a mean cover of 4% for the relevés representing this community.However, in relevé 1, Stoebe vulgaris has a mean cover of 42% , resulting in this relevé being classified as closed dwarf shrubland.If relevé 1 is not taken into ac count, the mean cover of Stoebe vulgaris is less than 1 % for the community as a whole, hence the com munity is classified as grassland.The floristic compo sition of relevé 1 is such that it forms a part o f Com munity 16 (Table 2).Stoebe vulgaris can be regarded as an invader species, without which relevé 1 would have potentially closer floristic affinities with Com munity 16.The presence of Stoebe vulgaris causes much concern amongst the local'farmers because of its encroachment upon grassland used for grazing.

Herbs
Herb species occurring in more than 50% of the relevés representing this community are:

2.2%
General Communities 13 to 16 are related to each other through the shared presence of the Senecio erubescens species-group (Table 2V) and Communities 8 to 16 are related to each other through the shared pres ence of the Schizachyrium sanguineum speciesgroup (Table 2W).The Stoebe vulgaris speciesgroup (Table 2U) indicates a partial affinity between Communities 15 & 16. Roux (1969) suggests that se lective grazing of grass results in grass tufts often being left ungrazed, which provides essential shade for Stoebe vulgaris seed germination.W here grass is grazed short and species composition is not affected, i.e. non-selective grazing (Acocks, 1966), Stoebe vulgaris will be unable to germinate for lack of shade.D. W oodland phase of Acocks's (1975) North-Eastern M ountain Sourveld on m oderately shallow soils, in moderately exposed habitats The woodland phase of Acocks's (1975) North-Eastern Mountain Sourveld is represented by one community in the study area, viz the Helichrysum nudifolium -Pro tea roupelliae Sparse Woodland.

17.
Helichrysum nudifolium -Protea roupelliae Sparse Woodland This woodland (Fig. 9) is found at altitudes of I 600 m to 1 900 m in the northern part of the study area (Fig. 3).It is represented by 17 relevés with 17 to 32 species per relevé.Relevés 120 and 118, al though floristically different from the rest of the community, are not regarded as a separate variation because of the lack of character species and because only two relevés are different.In order to ascertain whether structural differences exist, the two differ ent floristic units were illustrated separately as Fig. 4t, for relevés 120 and 118, and Fig. 4u for the rest of the community.This sparse-woodland community (Edwards, 1983) has an L structure (Ito, 1979; Figs 4t and 4u) with the greatest average cover of 36% for relevés 120 and 118, and 30% for the other relevés in the community, in the 0,0 m to 0,5 m height class.This community is exposed, being situated at a high altitude and considerable tem perature fluctuation could be expected.The moisture regime, however, should not be the driest in the study area although this community is much exposed, because of the fre quent occurrence of mist on the upper reaches of the Kransberg massif, as observed during the course of fieldwork.

Habitat
The soils are of the Mispah Form , Mispah Series, derived from sandstone o f the Aasvoelkop and Sandriviersberg Formations.The average soil depth varies from 70 mm to 180 mm and the surface rock cover varies from 50% to 80%.The terrain slopes up to 38° in a south-easterly to westerly direction.Relevé 12 2 representing the 0° slope is situated on a flat area at 1 750 m altitude.The electrical resistance of the soils varies from 4 300 ohms to 8 300 ohms and the T-value varies from 6,0 me/100 g to 11,8 me/100 g indicating a low to high nutrient status.It is sug gested that the high nutrient status occurs in bottom lands where runoff from the interfluves causes de pletion of nutrients on the interfluves and accumula tion of nutrients in the bottom lands.The soils are strongly acid (MacVicar et al., 1977) with pH from 4,4 to 4,9 when saturated with water.

Floristics
This community is differentiated by the Helichry sum nudifolium species-group (Table 2X) which does not occur in releves 120 and 118.The species diversity per unit area averages 6,2 species/m' for this community.It appears from aerial photographs of the study area that the vegetation represented by releves 120 and 118 falls into an apparent permanent shadow caused by the Kransberg cliffs and with ad ditional sampling could prove to be a variation of Community 17.

Trees and shrubs
The only conspicuous woody specics occurring in 50 per cent of the releves representing this com munity is: The mean percentage cover for Protea caffra is higher than indicated for a sparse woodland (Ed wards, 1983).However, the high cover can be attri buted to individual plants, under 2 m tall, as is also the case with Protea roupelliae which has a 47% con stancy and 1,3% mean cover.2Z) and the Helichrysum kraussii species-group (Table 2AA ), but the former species-group is not represented in relevés 120 and 118, whereas the latter is represented in these two relevés.Variation 11.2 and Communities 12, 17 and 18 are related to each other through the shared pres ence of the Helichrysum sp.Westfall 921 species group (Table 2AB).
The high altitude and steep slope on which this community is found, together with the high surface rock cover make accessibility and hence grazing by cattle difficult.The grass is not moribund, however, probably owing to periodic accidental fires.The grassland phase of Acocks's (1975) North-Eastern Mountain Sourveld is represented by one community in the study area, viz the Eragrostis race mosa -Trachypogon spicatus Grassland.
This grassland (Fig. 10) is found at altitudes of I 900 m to 2 080 m in the extreme north of the study area (Fig. 3).It is represented by 15 relevés with 19 to 35 specics per releve.This grassland community (Edwards, 1983) has an L structure (Ito, 1979; Fig. 4V) with the greatest average cover o f 18% in the 0,0 to 0,5 m height class.The community is exposed, being situated on the upper summit, and a wide tem perature range could be expected.As in the case of Community 17, the moisture regime should not be the lowest in the study area, although the com munity is exposed, because of frequent mists, as ob served during the course o f fieldwork.

Habitat
The soils are of the Mispah Form, Mispah Series, derived from sandstone o f the Sandrivtersberg For mation.The average soil depth varies from 40 mm to 100 mm and the surface rock cover varies from 60% to 90%.The terrain slopes up to 14° mainly in a south-westerly through northerly to south-easterly direction.The absence of a southerly aspect may be attributed to the cliff face to the south of the upper summit.The electrical resistance o f the soils is 4 200 ohms and the T-value is 11,0 me/100 g indicating soils of a high nutrient status which may be attri buted to the predominantly flat nature o f the upper summit which inhibits runoff and consequent loss o f nutrients.The soils are strongly acid (MacVicar et al., 1977) with a pH of 5,2 when saturated with water.

Floristics
This community is distinguished by the Trachypo gon spicatus species-group (Table 2Y).The species diversity per unit area averages 6,0 species/m!for this community. .

Trees and shrubs
Isolated Protea roupelliae trees and shrubs occur in 60% o f the relevés representing this community and the shrublet Fadogia monticola occurs with 60% constancy.Isolated Podocarpus latifolius trees are found in boulder clumps and the shrub Widdringtonia nodiflora occurs in 33% of the relevés.The can opy cover of the woody species is, however, less than 0 ,1 per cent, resulting in this community being classi fied as a grassland (Edwards, 1983).

Herbs
Herb species occurring in more than 50% of the relevés representing this Community are;  2Z) and the Helichrysum kraussii species-group (Table 2AA ).Variation 11.2 and Communities 12, 17 and 18 are related to each other through the shared presence of the Helichry sum sp.species-group (Table 2AB).

D ISC U SSIO N A N D C O N C L U S IO N S
The present study has resulted in a classification of the vegetation and a correlation of the main environ mental factors influencing the vegetation (Westfall et al., 1983).Although the vegetation is predominantly open woodland, the formation classes found in the study area range from forests to grasslands, with a diversity o f communities, along a temperature/mois ture gradient.Soil depth also appears to play an im portant role in community differentiation.The kloof forest communities are diagnosed by the species Celtis africana and Diospyros whyteana, whereas the w oodland com m unities representing A cocks's (1975) Sour Bushveld are distinguished by species such as Combretum molle, Faurea saligna, Ozoroa paniculosa and Heteropyxis natalensis.Species such as Burkea africana, Ochna pulchra and Strychnos pungens represent the Aristida aequiglumis speciesgroup (Table 2Q) and have a more restricted range than the species that distinguish the woodland phase of Acocks's (1975) Sour Bushveld.T he ordination of communities (Westfall et al., 1983) shows that the communities characterized by the Aristida aequiglu mis species-group (Table 2Q ) occupy a central posi tion on the temperature/moisture gradient.It can, therefore, be inferred that the extremes of the ternperature/moisture gradient are limiting factors for the species of the Aristida aequiglumis species-group (Table 2Q).The grassland phase of Acocks's (1975) Sour Bushveld, in the study area, appears to be re lated to the reduced effective soil depth resulting from seasonally high water tables.If the drainage were to improve, it is possible that an open-woodland formation could become established. Tinley (1977established. Tinley ( & 1982) ) also attributes the occurrence of grasslands in dambos to seasonal waterlogging.
The communities representing Acocks's (1975) North-Eastern Mountain Sourveld are found above 1 501 m altitude in the study area.Acocks (1975) de scribes North-Eastern Mountain Sourveld as having had a high-forcst climax.Isolated Podocarpus latifolius trees are found in Community 17, amongst boul der clumps (Fig. 11).The boulders probably afford protection from fire, Edwards (1967) describes the occurrence o f Podocarpus latifolius amongst boulder clumps in the Protea savanna in Natal as developing forest clumps.It is likely that Podocarpus latifolius could have a higher mean percentage cover, than at present, if protected from fire in Community 17, with the possibility of forest as a climax.
A comparison of communities described by Theron (1973), Coetzec (1975), Coetzee et al., (1976) and Van der Meulen (1979), who all worked in Transvaal Bushveid, shows that none of the com munities are similar to communities described in this study, in terms o f character species for the communi ties.A complete floristic comparison of the com munities described by the aforementioned authors and those in this study would entail joint synthesis of all the communities involved.
It would appear from the community descriptions that in an open bushveld situation, woody species encroachment could become a problem for grazing management, when the canopy cover o f the woody species is less than two crown diameters apart or more than 9% canopy cover forming a closed wood land.Although the floristic composition of the grass stratum appears different in Acocks's (1975) Sour Bushveld as represented in the study area, when the canopy cover of the tree stratum is greater than 20% for any height class (Fig. 4), it is likely that floristic change could take place before a 20% canopy cover is achieved.
The removal of the tree ferns, Cyathea dregei, from the larger kloof in which Community 3 is found, emphasizes the need for protection of the smaller kloof in which Cyathea dregei still occurs, if the species is to be conserved in its natural habitat in the study area.Although there is an abundance of streams in the study area, none are perennial.The experience gained at the Thabamhiope Research Station, near Estcourt in Natal (Westfall et al., 1982b) indicates that protection of kloofs from graz ing and fire should prolong the periods in which streams flow, which would be of benefit to the farms south of Kransberg.
The agricultural potential o f the study area ap pears to be limited because of the limited extent of deep soils, generally high surface-rock cover and lack of perennial free water.Furtherm ore, the grass cover is not suited to year-round grazing because of its sour nature (Booysen, 1967).That potential for agriculture appears limited, is supported by the many part-time farmers in the study area.Paddock fences generally do not follow natural community boundaries.This results in portions of camps being selected for grazing far more than others.Fences should be erected so that the enclosed vegetation is as homogeneous as possible to encourage uniform grazing.Where communities, such as Community 16, have local differences in veld condition with re spect to grazing, these could also be separated by fences to ensure uniform grazing.
Recommendations based on this study may be summarized as follows: 1. Species requiring conservation in their natural habitats include Cyathea dregei as well as Encephalartos eugene-maraisii which has been reported in the W aterberg (Coates Palgrave, 1977) and on the upper north-facing slopes of the Kransberg massif by local farmers, but not observed during the course of this study.
2. Protection of the catchment areas, from grazing by means o f fences and from fire by means of fire breaks, to improve the water supply.
3. Improvement of species composition o f the veld to enhance its grazing value and to overcome problems caused by invader species such as Stoebe vulgaris by ensuring that paddock fences coincide with community boundaries where feasible and ad justing grazing pressure as the proportion of Increaser species and Decreaser species dictates.
4. Provision of facilities for, and control o f activi ties o f sightseers, so that the landscape is not littered and species such as Cyathea dregei are not rem oved.
Conservation of the entire study area could achieve the abovementioned recommendations and might be feasible because o f the apparently low agri cultural potential o f the study area.Furtherm ore, conservation would ensure that Acocks's Sour Bush veld, which is poorly conserved (Edwards, 1974), could be represented in the W aterberg where the greatest area o f this veld type is found (Acocks, 1975).The study area includes the Kransberg massif which is frequently visited by members of mountain clubs, as witnessed during the course o f fieldwork, and is considered by mountain-club members to be probably the best rock-climbing facility in the Trans vaal.The study area is approximately 200 km from Pretoria which is an accessible range for visitors from Pretoria, Johannesburg and vicinity.Introduc tion of grazing game into the area would not im prove the grass species composition without a graz ing policy being implemented.Several private game reserves in the W aterberg area have a woody species canopy cover, including Dichroslachys cinerea thick ets which, from cursory observation, appear to be impenetrable.A grazing policy in which the species composition is frequently monitored and grazing pressure adjusted accordingly is, therefore, essen tial.A further advantage o f conservation of the study area is that the area could provide emergency grazing for farms in the Mixed and Sourish Mixed Bushveld (Acocks, 1975), in times of drought, but not on a perm anent basis.
In conclusion, the classification of the farm Groothoek, Thabazimbi District, has revealed a diversity o f plant communities and habitats requiring con tinual surveillance by farmers and conservation authorities if the full potential of the area is to be realized.
for the natural re source classification o f the D epartm ent o f Agricul tu re & W ater Supply.This veld type is found mainly in the W aterberg o f th e Transvaal and little is known about th e vegetation.T he study included classifica tion o f th e vegetation in term s o f both floristics and stru ctu re, as well as correlation o f the vegetation classification with the environm ent to facilitate later study o f th e entire W aterberg area.ST U D Y A R E A T he study area consists o f the farm G ro o th o ek 278 K Q situ ated betw een 24°28' and 24°31' south lati tude and 27°32' and 27°39' east longitude.T he farm covers approxim ately 4 000 ha o ver an altitudinal range o f 1 200 m to 2 100 m.T he sum m it of K ransberg form s the northern boundary with the greatest farm area consisting o f tw o plateaux a t a p proxim ately 1 500 m and 1 200 m altitude to the south.B akker's Pass lies to th e west allowing vehicu lar access to th e upper plateau.T h e K ransberg M assif consists o f sandstone from th e K ransberg Series o f the W aterberg System.O u t crops o f sandstone, shale and conglom erate from the N ylstroom Series o f the W aterberg System , are found o n th e upper plateau while sandstone o u t crops a re found o n th e low er plateau.A diabase dyke, o f post-W aterberg age, is exposedin B akker's Pass.T h e soils arising from these parent m aterials are mainly o f th e M ispah Form , Mispah Series.T h e topography and a north-south profile o f the study area are shown in Figs 1 & 2.

T
he study area is representative o f A cock's (1975) Sour Bushveld in a relatively undisturbed condition with sufficient variation in vegetation and environ m ent for observations to be relevant to o th er areas in th e W aterberg w here this veld type occurs.* B otanical R esearch In stitu te, D epartm ent o f A griculture & W ater Supply, Private B ag X101, Pretoria 0001.** D ep artm en t o f B otany, U niversity o f P retoria, P reto ria 0002.C L IM A T E

T
he vegetation was classified according to the B raun-B lanquet m ethod using th e P H Y T O T A B program package (W estfall et al., 1982a).T he main environm ental factors influencing the com m unities w ere ordinated on floristic d ata by d etrended corre-line of study area l-i.i i » i ■ i > 1 1 - J F IG .1. -T opographic m ap o f the farm G ro o th o ek .T habazim bi D istrict show ing b oundary o f th e study area Dl -S o u th profile of th e farm G roothoek, Thabazim bi d istrict orth-Soufh profile o f the farm G ro o th o ek , T habazim bi D istrict.
Cover o f stratah e rb > sh ru b > tree h e rb < sh ru b < tree h e rb < sh ru b > tree h e rb > sh ru b < tree h e rb = sh ru b = tree R E SU L T S Classification o f the vegetation, according to the B raun-B lanquet m ethod, revealed 21 (possibly 22) plant com m unities within five m ajo r vegetation types (T able 1).T he N orth-E astern M ountain Sour veld C om m unities (A cocks, 1975) a re outliers o f this veld type and are found above 1 500 m altitude on the K ransberg massif.T he phytosociological classifi cation o f com m unities is shown in T ables 2 & 3 w ith T able 2 showing the diagnostic species and T ab le 3 showing the general and infrequent species.Symbols denoting environm ental param eters a re shown above the m atrix in T able 2 and explained in A ppen dix A. Species with the highest m ean percentage cover p er com m unity are shown above the m atrix in T able 3. Percentage constancy and m ean percentage cover together with the densities o f trees greater than 2 m tall per relevé and p er h ectare, are shown to th e right o f the m atrix in both tables.T h e taxa on the left o f th e m atrix, in both tables, a re grouped into simplified life-form classes to facilitate the veld condition assessm ent o f the vegetation (W estfall et al., 1983).T he spatial relationships o f the com m unities are shown in the form o f a vegetation m ap (Fig.3).
to s o c io lo g ic a l c la ssifica tio n a n d h a b ita t c o rre la tio n * o f th e farm G r o o th o e k .T h a b a z im b i D is tric t, w ith diagnostic O

FIG . 3
FIG .3 -V egetation m ap o f th e farm G r o o t hock.T habazim bi D istrict.LI G1 ND K loof f o r e s t co m m unities o n m oderately d e ep soils in m o ist, sheltered habitats 1 occurring in m ore than 50% o f the relevés representing the com m unity are: unities 1 & 2 are related to each o ther through the com m on presence o f the Olea europaea spccies-group (Table 2C) a n d C om m unities 1, 2 & 3 are related to each o th e r through the shared p re sence o f th e Diospyros whyteana species-group (T able 2F), C om m unity 1 has no species-group in com m on with the o th er m ain vegetation types found in th e study a re a , which may be attributed to the low altitude o f C om m unity 1 and the surrounding vege tatio n not having been sam pled.It is, therefo re, sug gested that this com m unity could have a higher oc currence o f species in com m on with the low-lying valley vegetation.
Habitat T he soils are o f the M ispah Form , M ispah Series, derived from sandstone o f the Sandriviersberg F o r m ation.T he average soil d epth varies from 170 mm FIG . 5. -A n exam ple o f kloof forest v egetation in the west o f th e study a re a w ith Faurca saligna -Combreium molle O p en W oodland in the fore ground.
H erbs H erb species occurring in m ore than 50% of the relevés representing the com m unity are: Pleciranthus fruiicosus (forh) Cypenis albostriatus (sedge) Pieridium aquilinum (fern) Asplenium splendens (fern ) Pellaea calomelanos (fern) Carex spicato-paniculaia (sedge) G eneral C om m unities 2 & 3 are related to each o th er through the com m on presence o f the Myrsine afri cana species-group (Table C ) is differen tiating for th e w oodland com m unities representing A cocks's (1975) Sour Bushveld (m ain vegetation type B ). T h e grasslands o f Acocks's (1975) Sour Bushveld (m ain vegetation type C ) are related to the main vegetation type B through the com m on pres ence o f th e Schizachyrium sanguineam speciesgroup (Table2W), T he Aristida aequiglumis speciesgroup (T able 2Q ), which contains species such as Burkea africana and Ochna pulchra, has a narrow er ecological am plitude than the Combreium molle species-group (T able 2A C ) and is com m on to C om m unities 5 to 11.A n exam ple o f the vegetation is shown in Fig.6.In the phytosociologicai classification, the com m unities o f the m ain vegetation type B arc classified as follows (Tables1, 2

C
losed a n d O p en W oodlands U .( Khus demaia -Heieropogon comorius -Combreium molle C losed W oodland V aria tion 11.2 Chaetacamhus cosiaius -Heieropogon conlorius -Combreium m olle O p en W maximum -C om bretum m olle Closed Woodland T h is w o o d la n d is fo u n d a t a ltitu d e s o f 1 450 m -1 600 m on the low er slopes o f the K rans berg massif in the north o f the study area (Fig. 3). it is represented by ten relevés with 21 to 33 species F IG .6. -W oodland representa tive o f A cocks's (1975) Sour Bushveld with the Panicum m a x im u m -C o m b retu m molle C losed W oodland and Euclea crispa -Combreium molle C losed W oodland in th e foreground and th e Land olphia capensis -Combreium molle C losed W oodland in the background.
Fig. 4e) with the greatest average cover o f 23% in the > 3 m -5 m height class.Because th e com m unity is adjacent to C om m unity 4 , th e ir tem perature and m oisture regim es should be similar.H abitatT he soils are o f the Mispah F orm , M ispah Series, derived from sandstone o f th e A asvoëlkop F orm a tion.T h e average soil d epth varies from 150 m m to 240 m m and the surface rock cover varies from 20% to 60% .T he terrain slopes from 8° to 16° in a south erly to south-easterly direction.T he electrical resist ance o f the soil is 4 700 ohm s and the T-value is 8,5 me/100 g which is sim ilar to that o f C om m unity 4.
unities 2, 3 , 4 & 5 are related to each o th er through th e shared presence o f the Cyperus albostriatus species-group (Table 2H ) and C om m unities 5 to 11 are related to each o th er through the shared presence o f th e Aristida aequiglumis species-group (T able 2 0 )-Com m unity 5 together with Com m unity 4 form s a transitional vegetation zone betw een the m ain vegetation types A and B, T h e pioneer forbs present in C om m unity 4 (T able 2G ) a re absent in Com m unity 5. Selaginella dregei is present in tw o of the three relevés representing C om m unity 5 indicat ing th e high surface rock cover found in this com m unity.A lthough this com m unity is accessible to cattle, th e high surface rock cover may possibly re sult in a grazing preference for C om m unity 4. 6. Setaria megaphylla -C om bretum m olle Closed Woodland T his w oodland is found at altitudes o f 1 075 m to 1 375 m in an op en kloof in the east o f the study area (Fig, 3).It is represented by relevés 103, 101, 102 and 99 with 27, 26, 27 and 21 species per relevé re spectively.This closed w oodland com m unity (E d w ards, 1983) has a D structure soils are o f the M ispah form , M ispah Series derived from conglom erate o f the A lm a C rayw acke Form ation in th e case o f relevés 103, 101 a n d 102 and sandstone o f the A lm a G rayw acke Form ation in the case o f relevé 99.T he average soil d epth varies from 150 mm to 210 mm and the surface rock cover varies from 30% to 70% .T he kloof slopes from 3° to 5° in a southerly to south-w esterly direction.T he electrical resistance o f the soil is 4 300 ohm s with a T-value o f 9,3 me/100 g indicating soils o f a m oder ate nutrient status for the study area.T h e soils are strongly acid (M acV icar e ta l, 1977) with a pH o f 4,8 when saturated with w ater.

9. 2
T apiphyllum parvifolium -Landolphia cap en sis -C o m b retu m m olle Variation Fig. 41) with the greatest ave rage cover o f 5% in the lowest height class o f 0,0 m -0,5 m .Because the vegetation occurs on the low er sum m it, this com m unity is m ore exposed than the adjacent com m unities (C om m unities 8 & 9), and a greater tem perature range and a d rier moisture re g im e th a n in C o m m u n itie s 8 & 9 c o u ld be e x pected.

FIG
FIG. 7, -The Eragrostis pallens -Andropogon appendiculatusGrassland in the foreground with the north-facing slopes in the background.

FIG . 9
FIG .9, -T he Helichrysum nudifolium -Protea roupelliaeSparse W oodland o n the u p per slopes o f the K ransberg massif.
Herbs H e r b s p e c i e s o c c u r r i n g in m o r e t h a n 5 0 % o f t h e :le v é s r e p r e s e n t i n g t h i s c o m m u n i t y a r e :

FIG
FIG .10. -T h e Eragrostis race m osa -Trachypogon spicatusG rassland w ith a n isolatedPodocarpus latifolius in the cen tre.

sp. L im eu m viscosum Geigeria elongata P ortulaca kerm esina O steo sp erm u m ju cu n d u m A c h y ra n th es sicula P avonia colu m ella S en ecio o x yriifo liu s Gerbera am bigua Pearsonia cajanifolia S en ecio ru w en zo rien sis Crassula sarcocaulis H erm annia depressa I 90 80 11111111 66666667 6 3 9 8 2 7 1 0
Myrsine africana species-group (Table 2 E ), w hereas the Diospyros whyteana species-group (Table Combretum• molle, Vitex rehmannii, Bequaertiodendron magalismontanum and Brachylaena rotundata occur in all the relevés representing the com m unity, but have a m ean cover o f less than 2,5% . GeneralCommunities 13 to 16 are related to each other through the shared presence o f the Senecio erubes-cens species-group (Table2V) and Communities 8 to 16 are related to each other through the shared pres ence of the Schizachyrium sanguineum speciesgroup (Table2W).The Stoebe vulgaris speciesgroup (Table2U) indicates a partial affinity between Communities 15 & 16.
18 are related to each other through the common presence of the Protea roupel liae species-group (Table