S.Afr.J. Bot., 1990,56(1): 71-78 71 The identities of two confused species of Euphorbia (Euphorhiaceae) with descriptions of two closely related new species from Namaqualand L.C. Leach* and G. Williamson Karoo National Botanic Garden, P.O. Box 152, Worcester, 6850 Republic of South Africa and P.O. Box 499, Oranjemund, South West Africa/Namibia *Present address: Botany Department, University of the North, Private Bag X11 06, Sovenga, 0727 Republic of South Africa Accepted 5 October 1989 The identities of the confused and poorly known Euphorbia ephedroides E.Mey. ex Boiss. and E. spartaria N.E. Br. are established, amplified descriptions provided and variations and distributions discussed. Two varieties of E. ephedroides are described: var. imminuta Leach and Williamson and var. debilis Leach. Two closely related new species E. exilis Leach and E. glandularis Leach & Williamson, which had previously been confused with the foregoing are described and line drawings showing diagnostic features are provided. Die identiteite van die verwarde en swak-bekende Euphorbia ephedroides E. Mey. ex Boiss. en E. spartaria N.E. Br. word bevestig, uitgebreide beskrywings word voorsien en variasies en verspreidings word bespreek. Twee varieteite van E. ephedroides word beskryf: var. imminuta Leach and Williamson en var. debilis Leach. Twee nouverwante nuwe spesies E. exilis Leach en E. glandularis Leach and Williamson, wat vroeer met die voorafgaande spesies verwar is, word beskryf en Iyntekeninge wat die uitstaande kenmerke aantoon, word voorsien. Keywords: Arthrothamnus, Euphorbia, Euphorbiaceae, taxonomy *To whom correspondence should be addressed Introduction are as listed in the Index Herbariorum, Regnum Vegeta­ The species of Euphorbia sect. Arthrothamnus (Kl. & bile, 106 (1981). Gcke.) Boiss. are probably the most confused and poorly known of the genus as it occurs in S. Africa, and Euphorbia ephedroides E. Mey. ex Boiss. in DC. at the same time possibly the most widespread and Prodr. 15(2): 75 (1862), N.E. Br. in Flora Cap. 5(2): 282 difficult to identify. Consequently there are as many (1915), White, Dyer & Sloane, Succ. Euphorb. 1: 149 incorrect identifications as there are correct in most (1941) (Figure 1). Type: Drege 2949 in Herb. Bunge. herbarium collections. This position is not aided by the The Herb. Bunge specimen has not been located but an fact that almost, if not quite all, the species are normally ex numero duplicate (P) has been seen. unisexual, with a fair proportion of them known only from male specimens. Most of Boissier's species were Plant: a unisexual, unarmed, succulent shrub generally based on the Drege material published as nom. nud. by 0.5 m high (rarely up to 1.0 m), or in var. imminuta less E. Meyer (1843), which Boissier (1862) evidently than 0.1 m, branching from the base, oppositely, dichot­ considered to have been validly published and therefore omously or trichotomously rebranching; branches to have priority over the names published by Klotzsch & ascending erect, again rebranching somewhat distantly Garcke (1860) in their genus Arthrothamnus. Since above, the intervening sections often segmented, usually Boissier's concepts differed from those of Klotzsch & 2-3-jointed; branches and branch lets parallel sided, Garcke and it is Boissier's treatment which has been becoming successively reduced at the nodes, smooth, generally accepted, nomenclatural confusion is glabrous, yellowish-green to slate-grey, a thin reddish­ considerable. This position has apparently never been brown callus usually forming on the branching nodes. taken into account. Leaves spreading, estipulate, caducous, fleshy, glabrous, In this paper a start is made on the clarification of the narrowly oblong or elliptic, obtuse, sessile or shortly position with the establishment of the identity of E. petiolate, concave above, obtuse beneath, up to 8 mm ephedroides; its variation and distribution is discussed long, 1.5 mm wide. Inflorescence irregularly dichasial and an amplified description provided, together with the (sometimes limited to the original dichasium with cyme descriptions of two new varieties. The South West branches extending by repeated flowering). Bracts African/Namibian endemic: E. spartaria N.E. Br. is fleshy, longer, usually twice as long as the involucre, up similarly treated and two new species E. exilis Leach and to 4 mm long; petiole relatively narrow, expanding E. glandularis Leach & Williamson, which had abruptly into the ± orbicular, dorsally apiculate blade, previously been confused with the foregoing are adaxially shortly pubescent on the petiole and base of described. the blade, widely spreading, with the appearance of a Localities for cited specimens are as used for the Flora pair of ears when seen in vertical view. Involucre 2-3 of Southern Africa. The abbreviations used for Herbaria mm diam., 1.25-1.5 mm long, densely white villose 72 S.-Afr.Tydskr. Plantk., 1990,56(1) inside at the apex and down the rudimentary septa, Sandberg area in the extreme north of the Richtersveld green, eventually yellow, glabrous except for a small and neighbouring S.W. Africa/Namibia. Even at this patch of short pubescence opposite the bracts; glands 5, locality, one male plant [of three cultivated at KGW spreading, transversely elliptic, initially contiguous, (Karoo National Botanic Garden, Worcester)] was becoming separated as ovary or anthers develop, yellow­ typical of plants from the Soebatsfontein area, while green, ± 0.75 x 0.4--D.9 x 0.45 mm; lobes subquadrate, others conformed to the general pattern to be found on 0.3 mm long, irregularly obtusely toothed. Male flowers, Sandberg. The most differential character appears to be 15; pedicels pubescent; bracteoles plumose, equalling the the colour of the epidermis, light green to the south, pedicels; filament pale green, anther locules darker, darker greyish-green to the north but even here there are divergent, facing outwards, pollen pale yeIIow. Female distributional 'misfits', so that it becomes impossible to flower: abortive in male plants, shortly pedicellate, see any satisfactory groupings. glabrous; styles green, red tipped, usuaIIy only the tips The inflorescence and fruiting characters provide the exserted; in female plants: ovary subsessile, green, unifying factor in this so variable species, while there are glabrous; styles initially erect, free almost to the base, several 'marker' characters, the presence of which seems deeply bifid, becoming widely spreading with divergent positively to identify the species (although it must be yeIIow stigmas, again becoming erect when capsule remembered that absence is not necessarily significant), matures; capsule obtusely ellipsoid, not evidently lobed, e.g. jointed internodes, relatively large oblong or glabrous, becoming reddish-purple, with a dull surface narrowly elliptic cauline leaves and the subspherical or (not at all shiny) ± 4 x 4 mm. Seed dark brown, eIIipsoidal, not evidently lobed capsule, as well as the granulate-glebulose, lumpy and irregularly excavated, widely spreading long-petioled bracts aII appear to be dorsiventrally somewhat compressed ovoid, unequaIIy 4- unique among the slenderly branched species of sect. angled, dorsaIIy somewhat keeled; ventrally somewhat flattened with an indistinct suture, ± 2.5 mm long, 1.6 Arthrothamnus. Branching nodes enlarging and becom­ ing knob-like with age and usually covered by a mm wide, 1.1 mm thick. Euphorbia ephedroides is extremely variable in habit spreading brown caIIus seem also to be characteristic of and vegetative characters; on first impressions in the the species. field it seemed that at least two distinct species were Plants in coastal localities, mainly in the vicinity of involved, especiaIIy as distributional evidence appeared Alexander Bay are, however, considered to warrant to support this view. varietal rank in recognition of their low pulvinate habit, Southerly based plants are represented by erectly as also are the almost miniature plants from ± 16 km N. compact, rounded shrubs (near Wallekraal: narrowly of Rosh Pinah. erect) with yellowish to light green, more or less parallel, erect secondary branches and branch lets and from more Var. imminuta Leach & Williamson var. nov. ab northerly localities by darker greyish-green, more var. typica statura demissa, ramis ramulisque plerumque intricately branched shrubs with a tendency for branch­ decurvis; plantis maturis plerumque hemisphaericis ing to become widely forking rather than oppositely differt. branched and for branches to become more fleshy TYPUS.- Cape Province: Alexander Bay, G. & F. (softer) with internodes less frequently 'jointed'. Williamson 3652 (NBG, holotypus; K, PRE, isotypi). However, although several apparently significant characters are involved these appear to be developing in Var. imminuta is distinguished by its low habit with a south to north cline, culminating in plants from the drooping branches and branchlets; mature plants have a L-~ __~~ __~14mm Figure 1 Euphorbia ephedroides (1) Node and leaves; (2) bract; (3) male cyathium; (4) male flower and bracteole; (5) abortive female flower; (6) capsule; (7) involucral lobe; (8) seed; (9) styles. Leach & Hilton- Taylor 17013. S.Afr.J. Bot., 1990,56(1) 73 ± hemispherical appearance. A large plant near Holgat KGW, van laarsveld et al. 8607 (G, K, NBG, PRE); Kleinsee mouth (Leach & Williamson 16027) measured ± 300 mm road E. of Port Nolloth (-AC), Leach 16504 (K, NBG, PRE); in diam. X 75 mm high. Between Port Nolloth & Anenous (-AC), cult.