The genus Elephantorrhisa

The genus  Elephantorrhiza is reviewed. Nine species, including one new species, E. practermissa J H. Ross, from the eastern Transvaal, are recognized. A description of each species and a key to theidentification o f the nine species are provided. Lectotypes are selected for two species. The known distribution of each species is plotted and attention is drawn to the more serious deficiencies in ourknowledge of some of the species. Concern is expressed over the present conservation status of several species


INTRODUCTION
Elephantorrhiza, a small genus of nine species restricted to Africa south of the equator, was founded by Bentham. in Hook., J. Bot. 4: 344 (1841), on a specimen collected by Burchell (No. 2410) in the northern Cape Province.Burchell 2410 was also the specimen on which Burchell had earlier based his Acacia elephantina in his Trav. 2: 236 (1824), and on which De Candolle had based his Acacia elephantor rhiza in his Prodr. 2: 457 (1825).Although De Can dolle placed this specimen in Acacia, he was not altogether satisfied with the decision and questioned whether it was not perhaps a species of Prosopis. Sprengel, in Sys. Cur. Post. 4: 165 (1827), transferred De Candolle's species to Prosopis and later E. Mey., Comm.I: 165 í 1836), transferred Burchell's A. elephantina to Prosopis.
In founding Elephantorrhiza as a new genus, Bentham (I.e.) wrote: " . . .not only do the more pedicellate flowers, habit and foliage, remove it in appearance from Prosopis.but the pod described above (by E. Mey., I.e.) does not at all agree with that of Prosopis, which is multilocular, indehiscent, and does not separate from the sutures.The Elephantor rhiza is nearer in character to Adenanthcra, but the habit and the pod appear to me to be sufficient to warrant its being considered as a distinct genus.I have seen it only in flower" .
The last fairly comprehensive account of the genus was by Phillips in Bothalia 1: 187 (1923).Much material and information have become available since then but, despite this, the present state of knowledge of this essentially southern African genus leaves much to be desired.One of the aims of this paper is to draw attention to the more serious gaps in our knowledge in the hope that collectors will make an effort to collect the additional material and make the field observations necessary to enable a more comprehensive account of each species to be compiled.
In keying out species of Elephantorrhiza, emphasis is usually laid on the habit of the plants, that is, whether the plants are sufTrutices with unbranched aerial stems or whether they are shrubs or small trees with branched aerial stems.This is the character employed in the first dichotomy of the key and, as far as is known, it is a fairly reliable character.However, E. elephantina.which typically has unbranched aerial stems, may prove an exception when the growing apex has been damaged, because then the stems sometimes develop lateral branches.
Leaflet shape, size and, in particular, the position of the midrib in the leaflet, are of prime taxonomic significance in distinguishing the species.Number of pinnae pairs and, to a lesser extent, number of leaflet pairs arc also useful characters.Pod size, especially pod width, is of taxonomic significance, but in general the flowers in all species are fairly uniform.E. rangei is perhaps the exception in that it has larger flowers than the other species.The colour of the minute glands at the base of the pedicels is sometimes a useful character.
A genus of 9 species restricted to Africa south of the equator.Known only from the type collections.As typical var.glabra has not been re-collected for over fifty years, there is also concern about its current conser vation status.A thorough search in the type localities is necessary to establish whether the plant still sur vives.More material is desired.

KEY TO SPECIES
Codd 10119 from Bellevue farm near Twentyfour Rivers in the Waterberg District of the Transvaal resembles E. obliqua.The stem, petioles, rhachides and rhachillae are glabrous or almost so, and the leaves have up to 6 pinnae pairs and up to 19 pairs of leaflets per pinna.The leaflets are 9 -1 8 x 3 -4 mm, ± oblong, oblique basally with an excentric midrib and two other prominent veins arising from the leaflet-base, con spicuously venose and distinctly mucronate apically.Although leaflet shape differs somewhat from the leaflet shape of the syntypes, Codd 10119 is closer to E. obliqua than to any of the other species and, for the present, is referred to E. obliqua var.glabra.Un fortunately Codd 10119 is sterile.Further collections are required to indicate whether or not Codd 10119 falls within the range of variation of E. obliqua.
Found in South West Africa, Botswana, Rhodesia, Mozambique, the Transvaal, Orange Free State, Swaziland, Natal, Lesotho and Cape Province, (see Fig. 2).Occurs in grassland and open scrub; often gregarious.
As a selection of specimens from Botswana, Rhodesia and Mozambique was cited by Brenan & Brummitt in FI. Zamb. 3, 1: 27 (1970), no specimens from these territories are cited here.E. elephantina, commonly known as "Elandsboontjie", is the commonest and most widespread species.E. elephantina shows considerable variation in the number of pinnae pairs and in the number, size and shape of the leaflets.This variation appears to some extent to be geographical.There is a tendency for specimens from South West Africa, Botswana, the western portion of Rhodesia, the western Trans vaal, Orange Free State and northern Cape to have leaves with fewer than 10 pinnae pairs, fewer than 26 leaflet pairs per pinna and leaflets more than 8x 1 mm.The leaflets in these areas are frequently glaucous and the midrib is close to the distal margin basally but gradually becomes ± centric so that the leaflets are ± symmetric apically.In the eastern areas of Rhode sia, Mozambique, the eastern Transvaal, Swaziland and Natal there is a tendency for specimens to have leaves with more than 10 pinnae pairs, more than 26 leaflet pairs per pinna and leaflets less than 8 mm long and 1 mm wide.The midrib in these specimens is very close to the distal margin of the leaflets throughout their length as in E. suffruticosa and the leaflets are asymmetric apically.The Pretoria district of the Transvaal appears to be a critical area, for to the west the leaves tend to have fewer than 10 pinnae pairs and fewer pairs of large leaflets, while to the east the leaves tend to have more than 10 pinnae pairs and more numerous pairs of smaller leaflets.The extremes, for example Seydel 3761 from Oas in South West Africa and Wood 634 from Inanda in Natal, look very different but as there is ± continuous variation throughout and the individual characters often vary independently, no means has been found of delimiting the two groups satisfactorily.
The thick, red, underground root-stocks were at one time used for tanning and dyeing.Burtt Davy, FI. Transv. 2: 332 (1932), reports having dug up a rootstock ± 8 metres long at Vereeniging.
Although the exocarp of the ripe pod is fairly hard, it readily absorbs water and soon starts to disintegrate.Seeds often germinate within the moist disintegrating pods on the surface of the soil.The interesting and unusual type of germination of the seeds of E. ele phantina is discussed by Hofmeyer in S. Afr.J. Nat.Hist. 3: 215 (1921) and by Van der Schijff andSnyman in J. Arn. Arb. 51: 114(1970).
Found in Natal and Lesotho (See Fig. I).Occurs in grassland.
Phillips, in Bothalia I: 189 (1923), keyed out E. woodii under the species which are "shrubs or small trees with a distinct aerial stem" .As there is no information about the habit of the plants in Medley Wood's collector's book or on the herbarium sheets, it is thought that Phillips assumed E. woodii was a shrub or small tree because the aerial stems are branched.During recent years several attempts have been made to re-collect £. woodii in the type locality and eventually, in 1970, Mr R. G. Strey succeeded in finding a few plants.However, the plants were procumbent and not shrubby or arborescent as indicated by Phillips.The habit notes in the above description are based on the speci mens collected by Mr Strey and subsequently culti vated at the Natal Herbarium, Durban.Each year the branched, procumbent, aerial stems die back and are replaced by a new set of stems the following season.The stems are relatively weak and show no signs of as suming an erect posture.More field observations are required to establish whether E. woodii ever does grow as an erect shrub.At the time of collecting the living plants, concern was expressed for the future of the species in the type locality, at least, because the plants survive only in the narrow strips of uncultivated land which may themselves be cultivated at any time.
E. woodii is closely related to E. elephantina but differs in having branched, procumbent, aerial stems and leaflets with a slightly different venation.It differs from all the other species with branched stems in that the stems are procumbent and longi tudinally striate.Unfortunately not enough material is available to evaluate the taxonomic significance of the degree of pubescence of the stems, leaves and inflorescence axes as a means of distinguishing varieties within this species.

Key to Varieties
(a) var.woodii.Wilms 1973 (BM), collected between Pietermaritz burg and Newcastle in 1883, appears to be referable to E. woodii var.pubescens.However, the specimen has wider leaflets and a somewhat different facies to typical var.pubescens.More material is desirable but, as the specimen was not well localized, there seems little likelihood of further material being collected.
Cooper 2279, a flowering specimen with immature leaves, also appears to be referable to var.pubescens.Although recorded as being collected in " Basutoland," Cooper is not known to have been in present-day Lesotho.
Mogg sub PRE 9644, an immature and rather frag mentary specimen from Charlestown in northern Natal, is extremely difficult to place with certainty.The specimen in the Kew Herbarium consists of a single stem bearing axillary racemes and very young foliage, the details of which are scarcely discernible.The stem is 17,5 cm high, longitudinally striate and pubescent.The leaves have 2 pinnae pairs and up to 16 leaflets per pinna.The immature leaflets are up to 4,5 x 1,75 mm, the midrib is excentric basally and the leaflet-apex is distinctly mucronate.This specimen is hesitantly referred to E. woodii var.pubescens, but additional and better material from this area is required to establish the identity of the plants.
More material of var.pubescens, and from definite localities, is required.Pods would be of particular interest.
Found in Botswana, Rhodesia, Mozambique and the Transvaal (See Fig. 1).Favours rocky situations, in woodland, grassland and scrub.
As specimens from Botswana, Rhodesia and Mozambique were cited by Brenan & Brummitt in FI.Zamb. 3, 1: 27(1970), it is not considered necessary to cite specimens from these territories here.E. burkei differs from E. elephantina primarily in being a shrub or tree with branched, perennial, aerial stems and not a suffrutex with annual, un branched, aerial stems (unless damaged).The leafletbase in E. burkei is less asymmetric than in E. elephantina, and the midrib soon becomes i centric.The leaflets of E. burkei are typically larger than those of E. elephantina.E. burkei appears to have smaller seeds than E. elephantina, but more fruiting material is required to confirm this.
E. praetermissa appears to have a rather restricted distribution in the eastern Transvaal (see Fig. 1).Occurs on dry wooded hillsides.The first specimen of this plant was collected by Dr L. E. Codd in Sekukuniland in the eastern Trans vaal some fifteen years ago, and the second by Mr J. P. H. Acocks two years later.In response to an ap peal for fruiting material, Mr P. Vorster collected some excellent specimens earlier this year.
The specimens, which are fairly uniform vegetatively and appear to represent a distinct entity, cannot be accommodated satisfactorily within any of the existing species of Elephantorrhiza.There are a number of small differences which, collectively, distinguish the specimens from those of related species and appear to be of significance.
E. praeterniissa is most closely related to £. goetzei and to E. elephantina.Both £. goetzei and E. elephan tina occur in the eastern Transvaal but the specimens in question differ from the material of both of these species.
£. praeterniissa differs from typical £. goetzei in having consistently fewer pinnae pairs.Although from 3-41 pinnae pairs are recorded in £. goetzei, specimens with fewer than 12 pinnae pairs usually have large leaflets which are ± 4 -8 mm wide, and these have been separated as £.goetzei subsp.lata.The fewer pinnae pairs distinguish £. praeterniissa from typical £. goetzei, and the narrow leaflets distinguish E. praeterniissa from £. goetzei subsp.lata.The leaflets of £. praeterniissa differ from those of typical £. goetzei in having a somewhat thicker texture and in being ± sessile; the leaflets of typical £. goetzei usually have distinct petiolules.In £. goetzei the pods are long and narrow in proportion to their length (15-44x 1,3-2,4 cm) and, when mature, the position of the seeds is marked by distinct raised bumps.In £. praeterniissa the pods are shorter and broader (12-18x2-3,2 cm), ± compressed, and lack distinct raised bumps over the seeds.The seeds of £. praetermissa are ± compressed in constrast to the ellipsoid or lenticular seeds of £. goetzei, and they are smaller than those of the latter.Although the length of the racemes provides no discontinuity between the two species, the racemes of £. praeterniissa are consistently short and are much shorter than is usual in £. goetzei.
E. praeterniissa differs from £. elephantina in being a robust shrub 1-2 m high and in having branched aerial stems.The leaflets of £. praeterniissa differ slightly in texture and lack the ± conspicuous venation of typical £. elephantina.while the pods tend to be slightly narrower than is usual in £. elephantina.
Although £. praeterniissa is described as locally common by collectors, very few specimens have been collected.More material is required.

E. rubescens
As a selection of specimens from Tanzania, Angola, Botswana, Zambia, Rhodesia, Malawi and Mozam bique have been cited in recent regional floras, no further specimens from these territories are cited here.In the area delimited for Flora Zambesiaca £. goetzei frequently produces its flowers when the plant is leafless.In the Transvaal, however, £. goetzei usually produces flowers together with the leaves.
As leaves are required for establishing which subspecies specimens belong to, it is not possible to refer many of the leafless flowering specimens from the Flora Zambesiaca area to either subspecies with certainty.These leafless flowering specimens have been plotted under the category "subsp.uncertain" on the accompanying distribution map of £. goetzei (see Fig. 3).
It is possible that £. petersiana Bolle in Peters, Reise Mossamb.Bot.I: 9 ( 1861) is an earlier name for £. goetzei.If this were ever confirmed, then £. petersiana would be the correct name for this species.The holotype of £. petersiana, now destroyed, was a flowering specimen (without leaves) collected by Peters at Sena in Mozambique.Unfortunately the type description is too imperfect to enable the species to be positively identified.Bak.f., Leg. Trop. Afr. 3: 802 (1930) shed no light on the identity of £. petersiana.Burtt Davy, FI. Transv. 2: 332 (1932)  Known only from Zambia and Rhodesia (See Fig. 3).Occurs in woodland of various types.
The above description was drawn up from two isotypes in the SAM Herbarium.The extreme dimen sions given in square brackets were recorded by Harms in his type description.
There is considerable variation in leaflet size even on a single branch; the upper leaves often have small leaflets and the lower leaves larger leaflets.
E. rangei bears a superficial resemblance to E. suffruticosa but differs in having larger and broader leaflets in which the midrib is ± centric apically, slightly longer pedicels, and larger flowers.
E. rangei is known only from the type collection.It has never been re-collected since Jan. 1908 and the possibility exists that it is now extinct.A thorough search for this plant in the type locality is most desirable in an attempt to evaluate its present con servation status.
Known only from the Grootfontein District in South West Africa (See The original specimens on which Dinter based his description are no longer available for study.For tunately, however, both syntypes, namely Dinter 745 and 1689, are represented in the South African Museum collections.There is one sheet of Dinter 745 and three sheets of Dinter 1689.One of the sheets of Dinter 1689 is a mixed gathering consisting of a vege tative shoot of E. suffruticosa and a pod of E. schinziana, while the flowers in the capsule could belong to either species.On the second sheet of Dinter 1689 there is a vegetative shoot of E. schinziana with a mature pod attached and, in addition, there is a flowering specimen which is leafless apart from an extremely young leaf or shoot on which no details are discernible.In view of the mixed gathering of E. schinziana and E. suffruticosa on the first sheet of Dinter 1689, the possibility exists that the flowering specimen on the second sheet belongs to E. suffruti cosa and not to E. schinziana.It will be recalled that in South West Africa E. suffruticosa usually flowers when leafless.As none of the other specimens of E. schin ziana examined were in flower, the details of the flowers in the above description were taken from this second specimen of Dinter 1689.It is possible therefore that the flowers described are those of E. suffruticosa and not of E. schinziana.The third sheet of Dinter 1689 consists of a single leaf and two mature pods (the valves of one pod are mounted separately which gives the impression that there are three pods).
As the one sheet of Dinter 1689 is a mixed gathering, and as there is a possibility that a second sheet is also a mixed gathering, it seems desirable to select a lectotype for E. schinziana from the third sheet of Dinter 1689 or from Dinter 745.Dinter 745 is the better specimen of the two and consequently I now select Dinter 745 as the lectotype of E. schinziana.
There is a considerable variation in leaflet size on a single branch; some of the upper leaves often have distinctly smaller leaflets than the leaflets on the lower leaves.
Found in Angola, South West Africa, Rhodesia and Mozambique (See Fig. 1).Occurs in woodland, grassland and in broken country; often among rocks.The ecological preferences of E. suffruticosa are not clear and more information is required.
As specimens from Rhodesia and Mozambique were cited by Brenan & Brummitt in FI. Zamb. 3,1: 26 (1970), it is not considered necessary to cite speci mens from these territories here.
I have not seen the specimen from Huila, Dekindt 536 (LISC), hesitantly referred to E. suffruticosa by Torre in Consp.FI. Angol. 2: 263 (1956).The follow ing specimens from Angola have, however, been examined: The narrow leaflets of E. suffruticosa, with the midrib marginal throughout the length of the leaflet, are most diagnostic and enable this species to be readily distinguished from all of the other Elephantorr hiza species.
There appears to be a discontinuity in the distri bution of E. suffruticosa between eastern and central Rhodesia and South West Africa and Angola (See Fig. 1).No significant morphological differences have so far been noted between specimens from these two areas of distribution except for an inconsistent ten dency for some leaflets to be more acute and mucro nate in Rhodesia than in South West Africa and Angola.In addition, in specimens from Rhodesia there are usually ± conspicuous reddish or orange glands at the base of the leaflets, while in Angola and South West Africa the glands are inconspicuous and pale yellow or even absent.
In the Flora Zambesiaca area E. suffruticosa usually produces flowers together with the leaves, while E. goetzei usually flowers when leafless.The leaves which accompany the flowers in E. suffruticosa enable specimens of these two species to be readily distinguished in the Flora Zambesiaca area.Other wise it is sometimes difficult to differentiate these two species from flowers alone.The inflorescence axes in E. suffruticosa are often puberulous whereas in E. goetzei they are glabrous, and this character sometimes assists in the identification of specimens.
In South West Africa, however, E. suffruticosa frequently flowers when leafless, while in the Transvaal E. goetzei usually produces flowers together with the the leaves.In the area delimited for the Flora of Southern Africa, therefore, the reverse situation tends to prevail; E. suffruticosa flowering when leafless and E. goetzei producing flowers together with the leaves.Although E. goetzei has been recorded from Angola, it has not been recorded from South West Africa.
Schinz in Mém.Herb.Boiss.1:117 (1900) cited six specimens of E. suffruticosa and these specimens must all be regarded as syntypes.The syntypes are: Fleck 491a and 499a, Schenck 457, Schinz 2070 and 2071, and Rautanen 242.An examination of all the material of E. suffruticosa in the University of Zurich Her barium revealed that there are two sheets of Fleck 491a; one in flower and young pod collected in Octo ber 1891, and the other with mature pods and seeds plus the fragments of a leaf collected in January 1891.
Schinz (I.e.) was uncertain whether all of the above specimens belonged to the same taxon, and was there fore in some doubt about including them all under his E. suffruticosa.In particular, he expressed doubt about the specimen of Fleck 497a, with the robust ma ture pods, stating that they bore a resemblance to the pods of E. elephantina.As none of the specimens was regarded as complete, Schinz drew up his type description from all of the syntypes.In view of the doubt in Schinz's mind whether all of the specimens belonged to the same taxon, it seems desirable to select a lectotype for E. suffruticosa.
Owing to the difficulty of establishing the identity of leafless flowering specimens with absolute certainty, Schenck 457 and the flowering specimen of Fleck 491a have been eliminated as potential lectotypes as neither has any leaflets.Fleck 499a and Rautanen 242 are sterile and are not considered suitable for choice as lectotype either.The two best specimens are undoubt edly the Schinz specimens; one from " Kilevi am Kunene", just south of Humbe in Angola, and the other from Amutele in Amboland, South West Africa.However, neither of these specimens bears a collector's number.Both specimens were named E. suffruticosa by Schinz and the localities of collection correspond with the localities cited for the specimens of Schinz 2071 and 2070 respectively.There are no other Elephantorrhiza specimens in Schinz's collection from these localities, so it is considered safe to assume that these two specimens are the specimens he had before him and cited as Schinz 2071 and 2070.
Schinz drew attention to the specimen from Kilevi having immature pods and, as the pods on this speci men in question from Kilevi are immature, this supports the contention that this was the specimen Schinz was referring to.
The Schinz specimen from " Kilevi am Kunene" (number 2071), consisting of three leaves and two pods and having two inflorescences in the capsule mounted on the sheet, is the better of the two Schinz specimens of E. suffruticosa.Consequently, I now select Schinz 2071 from Kilevi am Kunene in Angola as the lectotype of E. suffruticosa.
Having arrived at this decision to regard Schinz 2071 as the lectotype of E. suffruticosa, I found it more than a little disconcerting to find that Schinz in Mém. Herb. Boiss. 1: 105 (1900) cited Schinz 2071 from Olukonda-Oshiheke, Amboland, South West Africa as one of the syntypes of Acacia arenaria Schinz.Fortunately I have examined this syntype of Acacia arenaria and can vouch for its identity.In any event, it seems unlikely that Schinz 2071 from Olukonda-Oshiheke in South West Africa, the syntype of Acacia arenaria, would ever be confused with Schinz 2071 from Kilevi am Kunene in Angola, the lectotype of Elephantorrhiza suffruticosa.It is as well, however, to draw attention to the existence of these two Schinz specimens, each numbered 2071.
Known from one gathering from the eastern Cape.

Capf.-3128 (Umtata): Umtata aerodrome (-D A ). Strey 11073
Strey 11073 does not appear to match material of any of the existing species.Like E. elephantina and E. obliqua.the specimen has unbranched aerial stems.Strey 11073 appears to differ from E. elephantina in having larger leaflets, and differs from E. obliqua in having larger leaves with more numerous pinnae and leaflet pairs, and leaflets without a conspicuous venation.More material, particularly fertile material, is required in order to make a positive identification.

CONCLUSIONS
The present state of knowledge of several species of Elephantorrhiza in southern Africa leaves much to be desired.Only the four most widespread species, namely, E. elephantina, E. burkei, E. goetzei and E. suffruticosa are fairly well collected and documented.Flowering and fruiting material of E. praetermissa has been collected, but more material is desired.The four remaining species, however, are inadequately known and there is concern about the present conservation status of all of them.
A list of the most serious deficiencies in our know ledge has been drawn up in the hope that collectors will make an effort to collect the material and in formation required to enable a more comprehensive picture to be compiled.
1. Pods of E. obliqua have never been collected.Both var.obliqua and var.glabra are known only from the type collections and no authentic material of either has been collected for over fifty years.More material of E. obliqua, particularly fruiting material, and information on the current conservation status of the species are required.
2. More material of E. woodii var.woodii, parti cularly fruiting material, is required.The pods of E. woodii var.pubescens are unknown.There is a need for flowering and fruiting material of var.pubescens and it is essential that the precise localities of collection are recorded.Ecological notes and infor mation on the current conservation status of both varieties of E. woodii are desirable.
3. The identity of the plants from northern Natal, which have hesitantly been referred to E. woodii var.pubescens needs elucidation.Additional and better material is required.
4. E. schinziana has not been re-collected since Jan. 1939.As it is not absolutely certain whether the flowers of E. schinziana have been collected, flowering material is most desirable.It would also be interesting to know whether or not E. schinziana flowers when leafless.More material, ecological notes and infor mation on the current conservation status of this species are required.
5. E. rangei is known only from the type collection (Jan.1908).More material, ecological notes and information on the current conservation status of the species are required.
6.More material of Strey 11073 from the Um tata aerodrome in the eastern Cape is required.