Two new species of Commiphora ( Burseraceae ) from southern Africa

Commiphora steyn ii Swanepoel and C. gariepensis Swanepoel, here described as new species, are known only from the Kaokoveld and Gariep Centres o f Endemism respectively. Illustrations o f the plants and distribution maps are provided. Diagnostic characters o f C. steyn ii include the pale ashy grey, non-peeling bark and the lack o f wart-like projections around the large lenticels. Diagnostic characters o f C. g ariepensis include the stamen number which varies between four and eight, and the milky-watery latex which does not squirt when branches are damaged. When without leaves or fruit, C. gariepensis can easily be confused with several other species. Comprehensive tables with diagnostic morphological features to distinguish between the new species and closely related taxa are presented.

viminea was sourced from the literature.Regarding C. merkeri, C. habessinica and C. spathulata, all informa tion presented was sourced from Gillett (1991).
Dioecious small tree up to 3.5 m high, with or with out spines; single or multi-stemmed from ground level; trunk and stems cylindrical, up to 200 mm in diam.Bark on trunk and older stems pale ashy grey, yellowish grey, greyish brown or khaki, smooth, peeling insignificant, in some specimens peeling in places in small, tough, flake-like pieces or in short, narrow, transverse strips, not papery', occasionally with few dark patches in places, lenticels transversely elongated, often almost completely encircling trunk and stems.Branches and branchlets gla brous, smooth, with small lenticels.shiny brown to dark brown, rarely maroon-brown or blackish grey, often with transversely alternating rings o f dark and pale bark on older branches, often spine-tipped, spines slender; spines or spine-tipped lateral branchlets rarely in clusters o f up to 5 or branched into 2 or 3 spines or spine-tipped lateral branchlets; new growth red or green, often with few glan dular hairs, otherwise glabrous; dw arf lateral branchlets often scarred.Exudate milky, glutinous, not aromatic, drying to form a soft to hard yellowish cream or caramelbrown resin, often in beads, not transparent.asymmetric, (0.5-)5.0-12.0(-15.0)x (0.2-)3.0-6.0(-8.0)mm, apex acute, base cuneate.margin entire: midrib con spicuous abaxially, broadest at base, gradually narrow ing towards apex, prominently raised adaxially, less so abaxially, on lateral leaflets often curved, especially over basal part, in minute lateral leaflets often obscure; leaves subsessile or petiolate; petiole with few' glandular hairs and long flexuous hairs adaxially, otherwise glabrous, from less than 1 mm up to 5 mm long, crescent-shaped in t/s with 7-15 vascular bundles, sectional dimensions (0.9-)1.1-1.5(-1.8)x (0.6-)0.8-1.1 (-1.3) mm: petiolules up to 1 mm long or leaflets sessile.
Inflorescence', flowers borne in clusters, solitary or male flowers rarely in much-reduced, simple or dichasial cymes with peduncle up to 1 mm long; axillary.Flowers sessile, subsessile or pedicellate: pedicel often with short glandular hairs: unisexual, hypogynous, precocious or appearing with or after leaves.Bracteoles and bracts nar rowly triangular, apex acute, w ith glandular and long hairs, bracteoles up to 1.5 mm long, bracts up to 2.3 mm long.
Fruit a drupe, obovoid, ellipsoid or oblong-ellipsoid, apiculate, slightly flattened, asymmetrical, 10-14 x 8-9 x 7-8 mm, apex occasionally bent over towards sterile lo cule; pericarp 2-valved; exocarp glabrous, not glutinous, reddish green or red in ripe fruit; mesocarp fleshy; putamen flattened, asymmetrical, ovoid, obovoid, ellipsoid or oblong-ellipsoid, with one fertile and one sterile locule, rugose; fertile locule often very rugose, 6.3-8.2 x 3.9-5.9x 3.    insignificantly only and is without the characteristic wart like projections around the large lenticels.At a distance, the bark appears pale ashy grey to white.Young branches are brown or blackish grey in colour.In C. viminea the bark peels around stems in significant, yellow, papery strips and young branches are purple.C. steynii is a small, single or multi-stemmed tree up to 3.5 m tall, with or without slender spines, whereas C. viminea is a larger tree up to 5 m tall, single-stemmed, always spinescent with robust spines.In C.
steynii the exudate is non-aromatic, whereas in C. viminea it is aromatic.The lamina margin on simple and terminal leaflets o f C. steynii are with up to 15 teeth on each side and the lateral leaflets are up to two thirds the length o f terminal leaflets.The petiole in C. steynii is usually thicker in t/s, 0.9-1.8x 0.6-1.3mm, and it has 7-15 vascular bundles.
In C. viminea.the lamina margin on simple and terminal leaflets has only up to 6 teeth on each side and the lateral leaflets are only up to half the length o f terminal leaflets, the petiole is usually smaller.1.0-0.8mm in transverse section and with 10 or 11 vascular bundles.The flowers and fruit provide additional distinguishing features.In C. steynii the pedicel and calyx are often with short glandular hairs and the pseudo-aril is yellow and fleshy, with four long, nar row arms.In C. viminea the pedicel and calyx are always glabrous, the putamen has the fertile locule narrowly ridged transversely one third from the base and the pseudo-aril is membranous, yellow, orange or red and covers the stone completely (Table 1)  C om m iphora gariepensis Swanepoel, sp.nov., C. ohlanceolatae Schinz habitu et foliis plerumque trifoliatis cum paucis simplicibus similis; exsudato lacteo-aquoso, non emicanti ubi rami laesi vel secti, foliolis terminalibus oblanceolatis ve; cultratis, lateralibus oblanceolatis, anguste ellipticis vel cultratis, lamina pro ratione latiori, staminibus 4 -8 in quoque flore difTert.Dioecious shrub or small tree, 0.6-3.0x 0.7-2.2m; trunk short, branching repeatedly above ground level into thick stems with succulent appearance; younger branches slender.Bark greenish brown, greenish grey or pale grey with small dark spots and longitudinal, narrow, dark markings in places, transverse folds at base o f stems and at bends o f older branches, usually with few parallel longitudinal ridges on stems and older branches in places, otherwise smooth, not peeling.Branches glabrous with few small lenticels, glutinous when young, not spine- tipped.Exudate watery-milky (initially watery, followed by a milky secretion), not squirting upon branches or branchlets being damaged or cut, glutinous, aromatic, forming a soft, transparent, pale cream-yellowish resin.
Inflorescence: flowers borne in much reduced or short simple dichasial cymes, up to 3 mm long, glandular, or flowers solitary, axillary.Flowers sessile, or when solitary, subsessile or pedicellate, unisexual, perigynous, appearing before leaves and often continuously while in leaf.Bracteoles ovate, up to 0.4 mm long, apex acute, glandular.Calyx green, continuous with hypanthium, glandular otherwise glabrous, lobes triangular to ovate, apex acute.Petals green to yellowish green, occasionally sparsely glandular, otherwise glabrous, narrowly elliptic or narrowly obovate, recurved apically but the minute tip inflexed, inserted on hypanthium.Disc cylindrical, with 4 fleshy lobes, adnate to hypanthium but distal part o f lobes free.Male flowers 2.6-4.7 mm long with pedicel up to 0.3 mm long; calyx 2.1-3.3 mm long; calyx lobes 0.8-1.3mm long; petals 2.6-4.8x 0.8-1.6 mm; disc lobes with apices distinctly to obscurely bifid; stamens 4 -8 , 4 long ones with filaments 1.1-2.9mm long, inserted on top o f disc lobes, \ ^\ short ones with filaments 0.6-1.8mm long, inserted on top o f disc between lobes, short stamens rarely completely absent; anthers 0.7-1.3mm long, equal in length on short and long stamens; filaments rarely flattened and broadened over lower part; gynoecium rudimentary.Female flowers 2.5^4.0 mm long; pedicel up to 0.7 mm long; calyx 2.3-2.9 mm long; calyx lobes 0.8-1.0mm long; petals 1.3-2.5 x 0.7-1.2mm; disc lobes distinctly bifid to entire; staminodes present; ovary half inferior; style variable in length from relatively short to relatively long, sutures deeply grooved; stigma obscurely 4-lobed; pistil with stigma from 0.9 mm below top o f flower to level with top o f flower, 1.7-2.4x 0.9-1.2mm.

T
A B L E 1.-S a lien t m o rp h o lo g ica l d ifferen ce s b etw een Com m iphora steyn ii and C. vim inea
. A study o f herbarium material in PRE shows that collections from the Zambezi River Valley are true C. viminea and not C. steynii.These plants also have the typical peeling bark with black patches characteristic o f C. viminea.Eponymy: the specific epithet honours Marthinus H. Steyn.bom in 1935, tree enthusiast, amateur botanist, author and publisher o f A field guide, southern Africa, Commiphora (2003).and various other field guides on southern African trees.Marthinus was the first person to propose that C. steynii should be regarded as a dis tinct taxon (Steyn 2003).I would like to propose the names ring-bark corkwood and ringbaskanniedood as the English and Afrikaans vernacular names, respectively.Distribution: C. steynii is only known from the Kaokoveld Centre o f Endemism (Van Wyk & Smith 2001), in northwestern Namibia (Figure 5).It most prob ably also occurs in southern Angola, as it was collected within only 1 km from the Namibian Angolan border near Ruacana in the Kunene River Valley.C. steynii va ries from locally common to uncommon or rare within its range.It is absent from many areas with seemingly suitable habitat.Habitat and ecology: C. steynii occurs in the Kaokoveld.including the pro-Namib Desert, the escarp ment and to the east on the inland plateau.It occurs 70-260 km from the coast at altitudes o f 800-1 200 m.where the annual rainfall is 75-300 mm.It grows mainly in Colophospermum-Commiphora woodland, where it prefers rocky areas and mixed soil and gravel substrates on hill slopes and plains.In the extreme south o f its range at Palm and Gomakukous. it occurs on Etendeka basalt of the Damaraland Igneous Province.In the Sesfontein area, it grows on sedimentary dolomite and metasedimentary schist o f the Damara Supergroup and in the Omuhiva area on calcrete.South o f the Steilrandberg and in the Rooidrom area it occurs on quartzite o f the Damara Supergroup.In the northeast o f its range at Ruacana. it is found on limestone o f the Karoo Supergroup(Miller &
ohlanceolata due to the similarity o f the leaves.However, the geographical dis tribution o f the two taxa differs markedly, C. gariepensis being restricted to the Gariep Centre o f Endemism and C. ohlanceolata to the northern Central Namib and the Kaokoveld Centre o f Endemism (Van der Walt 1986).Herbarium specimens o f C. dinteri and C. gariepensis with leaves only, could also be confused.However, the leaves o f C. dinteri are ± twice as broad as those o f C.

disc lobes, just below apex Always Never Inserted half way up on outside o f disc lobes Never Always Filaments: shape over basal part Flattened & broadened Never Always
PistilLength (mm) 1.7-2.83.0-3.

TABLE 3 .-Selected morphological differences between Commiphora steynii, C. viminea. C. merkeri, C. habessinica and C. spathulata Bothalia 36,1 (2006) 51 Character States C. steynii C. viminea C. merkeri C. habessinica C. spathulata
Diagnostic characters and affinities: C. gariepensis has the same habit as C. ohlanceolata and C. gracilifrondosa Dinter ex J.J.A.van der Walt, but differs from them mainly in the shape o f the leaves, in the morphology o f the flowers and in the type o f exudate.All three o f these taxa have trifoliolate leaves, but C. gariepensis and C. have simple leaves in addition.Trifoliolate leaves in C. gariepensis have the lamina on terminal leaflets oblanceolate or rarely cultrate with up to 11 teeth on each side o f the margin, whereas the lamina in lateral leaflets is narrowly elliptic, oblanceolate or cultrate to broadly cultrate with up to nine teeth on each side o f the margin.In C. ohlanceolata the lamina on both terminal and lateral leaflets is always oblanceolate, with up to 45 and 38 teeth respectively on each side o f the margin.In C. gracilifrondosa, the linear or cultrate leaflets, very variable in size and form, distiguish it from the other two taxa.The leaves o f some specimens o f C. gariepensis and C. gracilifrondosa resemble each other superficially (Figures 7 & 8).However, the leaves o f C. gariepensis are broader than those o f C. gracilifrondosa for corre sponding length.In C. gariepensis the flowers are borne in much reduced or short cymes up to 3.0 mm in length, in C. ohlanceolata in thyrses or cymes up to 13 mm long and in C. gracilifrondosa on cymes up to 50 mm long.The flowers o f C. gariepensis have 4-8 stamens per flower, whereas those o f C. ohlanceolata and C. gracilifrondosa have four stamens only.Unlike C. ohlanceolata and C. gracilifrondosa, the latex o f C. gariepensis is milkywatery (not watery) and does not squirt when branches or branchlets are damaged or cut.When without leaves or flowers, C. gariepensis is virtually indistinguishable from C. gracilifrondosa with which it shares the same habitat.The only notable difference then between the two taxa, is the milky-watery exudate which does not squirt in C. gariepensis, as opposed to being copious and only watery in C. gracilifrondosa.Although they share the same habitat throughout the known range of C. gariepensis, C. gracilifrondosa is common and much more widespread.Some specimens o f C. gariepensis could easily be mistaken for C.