zyxwvutsrqpo zyxwvutsrqp zyxwvuts zyxwvuts zyxw zyxwv BolanicalJoumal oflhe Ltnneun Soaep (1999), 130: 37-42. With 2 figures Article ID: bojl. 1998.0225, available online at http://www.idealibrary.com on I DE * @ R. 0. MOFFETT FLS Downloaded from https://academic.oup.com/botlinnean/article-abstract/130/1/37/2557314 by guest on 24 May 2020 A new species of Rhus (Anacardiaceae), endemic to serpentine near Barberton, Mpumalanga (Eastern Transvaal), South AErica zyxwvuts Department o f Botay, Universip o f the North (Qwaqwa Campus), P/Bag X I 3, Phuthaditjhaba, 9866, Republic Df South A h c a Received Febmuy 1997; acceptedfor publication August 1998 Rhus pygmaea, a new species endemic to amphibolitic serpentine soils near Barberton, Mpumalanga (Eastern Transvaal) is described and illustrated. It has affinities with R. pondoensis Schonl., but differs primarily in its dwarf habit, narrower leaflets, reduced inflorescence and male flowers having a conical pistillode. 0 1999 The Linnean Society of London ADDITIONAL KEY WORDS:-Amphibolite - nomenclature - taxonomy. zyxwvu CONTENTS Introduction. . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . Rhus pygmaea Moffett sp. nov. . . . . . . . . . . . . . . Discussion . . . . . . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . 37 39 39 39 41 42 INTRODUCTION Throughout the world serpentine soils are renowned for their distinctive flora (Wild, 1978). These soils also occur in South Africa, and pioneering studies by Morrey and Balkwill on the Mpumalanga serpentines have confirmed the uniqueness of these soils and their flora (Balkwill & Cadman, 1988; Morrey et al., 1992; Balkwill et al., 1997). In the latter publication, the following taxa are listed as endemic to the Barberton serpentine: Aystasia subb8ora C.B. Clarke (Acanthaceae) BerW2ga coddii Roessler (Asteraceae) Email: moffett@uniqwa.ac.za 0024-4074/99/050037 f 0 6 $30.00/0 37 0 1999 The Linnean Society of London 38 zyxwvutsrqpo zyxwvut zyxwv R. 0. MOFFE'IT 12 14 16 20 18 22 24 26 28 30 32 34 18k 18 20 20 22 26 28 30 32 34 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Figure 1. South Africa, showing the boundaries of the new provinces and the location of Rhus pypaea near Barberton, Mpumalanga. Downloaded from https://academic.oup.com/botlinnean/article-abstract/130/1/37/2557314 by guest on 24 May 2020 24 zyx zyxwvu Berkhqa zqheri (Sond. & Harv.) Oliv. & Hiern var. rogersiuna (Thell.) Roessler (Asteraceae) Berkhqa sp.nov., near B. seminivea Harv. & Sond. (Asteraceae) Brachystelma dyeri K. & M. Balkwill (Asclepiadaceae) Cyphia bolusii E. Phillips (Lobeliaceae) Dicoma sp. nov. (Asteraceae) Indigofera crebra N.E. Br. (Fabaceae) Ocimum (Becium) sp. nov., near B. obovatum E. Mey. ex Benth. (Lamiaceae) Ozoroa barbertonensis Retief (Anacardiaceae) Ozoroa sp. nov. (Anacardiaceae) Sartidia sp. nov. (Poaceae) Senecio sp. nov., near S. anomolochrous Hilliard (Asteraceae) Senecio sp. nov., near S. coronatus (Thunb.) Harv. (Asteraceae) T o this list is now added Rhuspygmaea, which was first briefly described in Flora of Southern Africa as Rhus taxon H., (Moffett, 1993). Although at that time it was regarded as unmistakable, it was felt that further study in situ was necessary before formally publishing it as a new species. The necessary field work was done near Barberton in April 1995 when it was confirmed that it was indeed a new species. (Fig. 1). zy zyxwvuts zyxw NEW SPECIES OF RHUS FROM SOUTH AFRICA DESCRIPTION 39 Rhuspygmaea Moffett sp. nov. (Fig. 2) dioecious, dwarf, rhizomatous, evergreen shrublet, 10-20 cm high; shoots arising from subterranean woody branches of a central swollen axis; aerial branches chestnut brown, glabrous to pubescent on young shoots, lenticellate, bark sometimes peeling. LEAVES crowded, trifoliolate, petiolate; petiole glabrous, convex below, shallowly canaliculate above, 2-7 mm long; leaflets sessile, coriaceous, glabrous, concolorous, grey-green, amphistomatous; lamina linear to lanceolate, occasionally oblanceolate, base narrowly cuneate, apex acuminate, prominently cuspidate; margin entire, thickened, pale cream, venation simple craspedodromous, midrib prominent above and below, secondaries prominent below, 6-8 per cm; terminal leaflets 1 6 4 7 m m long, 1-3.5mm wide, lateral leaflets 14-42mm long, 1-3mm wide. INFLORESCENCE axillary, much reduced, cymose, up to 10 flowers in males, up to 6 flowers in females. FLOWERS pedicellate, bracteolate, 5-merous, unisexual, discoid; calyx segments free, imbricate, glabrous, grey-green, ovate, 1 mm long, 0.5 mm wide; corolla segments free, imbricate, glabrous, yellowish-green, narrowly ovate, 2 mm long, 1 mm wide; disc patelliform, 10-crenate; male flowers with 5 interpetalous stamens, filaments linear, anthers introrse, dorsifixed, 2-thecate, pistillode conical; female flowers with 5 short staminodes, ovary oblique to subglobose, styles 3, very short, persistent, stigmas minutely capitate. FRUIT asymmetric, slightly compressed, glabrous drupe, red above, green below when fresh, brown, wrinkled when dry, 7 mm wide, 4 mm thick, styles remaining as 3 minute tubercles. PLANT ‘@e. Downloaded from https://academic.oup.com/botlinnean/article-abstract/130/1/37/2557314 by guest on 24 May 2020 Rhus taxon H. Moffett. Flora ofsouthern Afica 19.3.1: 119 (1993). R. pondoensi Schonl. affinis, sed habitu nano vix usque ad 20cm attingenti non plerumque usque ad 100 cm, ramis non striatis, foliolis anguste lanceolatis non late lanceolatis, inflorescentia cymosa simplici pauciflora non paniculata, et floribus masculinis cum pistillodiis dflert. zyx zyxwvutsr zyxwvu Near Agnes Mine, Barberton, Mpumalanga (Eastern Transvaal), 13.iv.1995, Moffett 4905 (PRE holo, K iso). Distribution and habitat. Restricted to amphibolite serpentine west and north-west of Barberton, Mpumalanga, where it occurs in grassveld. Specimens seen. Balkwill & Cadman 26 1 1, Queen’s River, Barberton (NU); Balkwill, Cudman &3 Marry 3728, in the valley above Agnes Mine, 1000 m, 2.v. 1987 (J,PRE); Moffett 4903, between Agnes Mine and Twello pine plantations, 13 km west of Barberton, llOOm, 13.iv.1995 (MO, NBG), 4904 ibidem (J, PRE), 4906 ibidem, 1300 m (PRE, K). DISCUSSION It appears that ultramafic soils promote dwarfism in shrubs as the only other species of Rhus that does not exceed 20 cm in height is R. wildii R. & A. Fernandes, which occurs on an exposed chrome ridge in Mpingi Pass near Sipolilo, Zimbabwe 40 zyxwvutsrqpon R. 0. MOFFETT Downloaded from https://academic.oup.com/botlinnean/article-abstract/130/1/37/2557314 by guest on 24 May 2020 zyxwvutsrq zyxwvutsrqpo zyxwvu zyxwv zyxw Figure 2. Rhus pygmaea sp. nov. A, female flowering shoot, Moffett 4906. B, male flowering shoot, Moffett 4905. C, habit, Moffett 4903. D, male flower, Moffett 4905. Scale bars in A,B,C = lOmm, in D = 1 mm. zyxwvut zyxw NEW SPECIES OF RHUS FROM SOUI'H AFRICA 41 Downloaded from https://academic.oup.com/botlinnean/article-abstract/130/1/37/2557314 by guest on 24 May 2020 zyxwvutsrq zyxwvu zyxwv Figure 3. Habitat of Rhus pygmaea sp, nov. Valley above Agnes gold mine, Barberton, looking south towards Twello pine plantations. Serpentine outcrops sweep from right to left in the centre and foreground of the picture. The lighter band in which R. pygmaea occurs, is amphibolite and the darker band below it with scattered dark shrubs, is dunite. (Fernandes & Fernandes, 1966). Ozoroa barbertonensis and an unnamed Ororoa sp. are also serpentine dwarf members of the Anacardiaceae, a family better known for its shrubs and trees. R. pygmaea proved very difficult to find as it grows in dense grassveld 2-3 times its height. Future botanists looking for this species would do well to first look for accompanying and more prominent species such as Sporoboluspectinatus Hack., Asystasia subbgora, Berkhqa coddii and B. zgheri var. rogersiana in the lighter amphibolite band that runs through the valley from south-west to north-east (Fig. 3). The darker band below is a dunitic serpentine without R. pypmaea. Prominent in April in this darker band was Jamesbrittenia grandgora (Galpin) Hilliard (Scrophulariaceae) in full flower. The presence of a pistillode in the male flowers of R. pygmaea is unique and has not been recorded or seen by the author in any other African Rhus species. The restricted occurrence of R. pygmaea and the other endemic taxa listed above in an area largely unprotected from development, highlights the vulnerability of the Barberton serpentine flora. Only 6.4% of a total of 137 km' of serpentine flora in Mpumalanga is found in a proclaimed nature reserve (Balkwill et al., 1997) and it is therefore imperative that this unique flora be adequately studied and protected. ACKNOWLEDGEMENTS I am grateful to the Research Committee of the University of the North (Qwaqwa Campus) for funding my travel costs and to Mike Botha of Lomati Forest Products, 42 R. 0. MOFFETl' Barberton, who gave me permission to collect on Twello property. Kevin Balkwill, curator of the C.E. Moss Herbarium at the University of the Witwatersrand, drew my attention to this species and made valuable suggestions to improve this paper. Elaine Taylor, formerly of Harrismith and now of White River, was responsible for the drawings in Figure 2. Hugh Glen and Ted Oliver of the National Botanical Institute helped me with the Latin diagnosis. Downloaded from https://academic.oup.com/botlinnean/article-abstract/130/1/37/2557314 by guest on 24 May 2020 zyxwvu zyxw zyxwvu REFERENCES zyxwv zy zyxwvutsrq zyxwvuts Balkwill K, Cadman M-J. 1988. Studies on serpentine flora: a new species of Brachystelrna (Asclepiadaceae). South Ahcan Journal OfBotary 54: 60-62. Balkwill K, Williamson SD, Kidger CL, Robinson ER, Stalmans M & Balkwill M-J. 1997. Diversity and conservation of serpentine sites in southern Mpumalanga (Eastern Transvaal), South Africa. In: Jaffre T , Reeves RD, Becquer T, eds. 7he ecolosy of ultrarnajic and mutall@rous arpIIs. ORSTOM Nournla, Docurnenb Scientjfiques et irechniques III(2): 133- I 38. Fernandes R, Fermandes A. 1966. Rhus L. In: Exell AW, Fernandes A, Wild H, eds. Flora zarnbesiaca vol. 2.2. London: Crown Agents for Oversea Governments and Administrations, 590-6 15. Moffett RO. 1993. Rhm (Anacardiaceae). In: Leistner OA, du Plessis E, eds. Flora ofsouthern Africa 19.3.1: 1-129. Morrey DR, Balkwill K, Balkwill M-J, Williamson S. 1992. A review of some studies of the serpentine flora of southern Africa. In: Baker AJM, Proctor J, Reeves RD, eds. 7he oegttation of ultrarnajic (serpentine) soils. Proceedings of the FirJ-t Inleniational Conference on Serpentine Ecolo~.Andover, Hampshire: Intercept, 147-157. Wild H. 1978. The vegetation of heavy metal and other toxic soils. In: Werger MJA, ed. Biogeography and ecology ofsouthem AJbca. The Hague: Junk, 1301-1332.