Telopea 11(3) 390-391 Short Communication A new combination in Clematicissus Planch. (Vitaceae) Betsy R. Jackes and Maurizio Rossetto 1 2 ' School of Tropical Biology, James Cook University, Townsville, Qld 4811, Australia 2 National Herbarium of New South Wales, Botanic Gardens Trust, Mrs Macquaries Road, Sydney NSW 2000 Australia. When the genus Cissus was revised (Jackes 1988) the decision was made to retain the species Cissus opaca F.Muell. in the genus until molecular studies indicated its true affinities. Cissus opaca, an eastern Australian species, shares a number of morphological features with the Western Australian species Clematicissus angustissima (F.Muell.) Planch., and with the South American species Cissus tweedieana (Baker) Planch. These features are: a vine or sprawling shrub; tuberous roots; great variation in size and shape of adult leaves even within the same population; inflorescences arise from one or both branches of a leaf-opposed tendril and flowers are 5-merous. Many of these characteristics are also exhibited by both subspecies of Rhoicissus tridentata (L.f.) Wild 8c Drumm (Urton et al. 1986). Clematicissus angustissima can be distinguished from Cissus by the 5-merous flowers, the presence of the inflorescence arising on the tendi ils and the structure of the endosperm., as well as from most species of Cissus, as cunently circumscribed, by the compound leaves and the fruit which often has more than 1 seed, features also shared by C. opaca. Cissus opaca also exhibits considerable variation in lea morphology between juvenile and adult leaves in young plants arising from seed as well as in aerial parts developing from the resprouting of the underground tuber; this ea polymorphism is particularly noticeable for individuals growing in moist situations. Phylogenetic analyses by Rossetto et al. (2002) using sequence data from plastid (the trnL intron) and nuclear (ITS 1) DNA strongly supported a clade comprising Cissus opaca and Clematicissus angustissima as being separate from the other Austra nm species analysed. Thus a new combination is required. Subsequent studies incicatc that Cissus tweedieana forms a clade sister to Clematicissus along vvith Cissus stuata Ruiz 8c Pav., another South American species (Rossetto et al. submitted). A stu v y Soejima 8c Wen (2006) indicated that Cissus striata was closely related to severa species of Rhoicissus. Further studies, particularly molecular and developmental, aie lequirc to resolve these relationships. Clematicissus opaca (F.Muell.) Jackes 8c Rossetto comb. nov. Basionym: Cissus opaca F.Muell., Trans. & Proc. Philos. Inst. Victoiia 3. 23 (1859). Holotype: Brigolow [sic] scrub of eastern Australia (MEL 539836). © 2006 Royal Botanic Gardens and Domain Trust ISSN0312-9764 391 Telopea 11(3): 2006 Jackes & Rossetto Key to the species of Clematicissus Flowers in a loose umbel, endosperm in transverse section W-shaped, New South Wales and Queensland . C. opaca Flowers in a contracted umbel or head, endosperm in transverse section U-shaped, Irwin District Western Australia . C. angustissima Both species are illustrated in Austrobaileya 2(5): 497 (Jackes 1988) and Austrobaileya 3(1): 102 (Jackes 1989) respectively. References Jackes BR (1988) Revision of the Australian Vitaceae, 3 Cissus L. Austrobaileya 2:481-505. Jackes BR (1989) Revision of the Australian Vitaceae, 4 Clematicissus Planchon. Austrobaileya 3: 101-102. Rossetto M, Jackes B, Scott KD 8c Henry RJ (2002) Is the genus Cissus (Vitaceae) monophyletic: evidence from plastid and nuclear ribosomal DNA. Systematic Botany 27: 522-533. Rossetto M, Crayn DM, Jackes BR 8c Porter C (submitted ) Molecular evolution of the Australian Vitaceae. Canadian Journal of Botany. Soejima A 8c Wen J (2006) Phylogenetic analysis of the grape family (Vitaceae) based on three chloroplast markers. American Journal of Botany 93: 278-287. Urton NR, Olivier MC 8c Robertson BL (l986) The taxonomy of the Rlwicissus tridentata (Vitaceae) complex in southern Africa. South African Journal of Botany: 52:389-396. Manuscript received 26 May 2006, accepted 21 July 2006