A CHECKLIST OF THE GENUS TARENNA GAERTN. (RUBIACEAE) IN THAILAND (W. KESONBUA & P. CHANTARANOTHAI)
Enumeratio (Craib, 1932), but no key was provided. No recent treatment is available and the lack of a revision has led to difficulty in the identification of Thai species. To remedy this, this study gives an overview of all Thai species, information on their ecology and distribution as well as a key for identification.
Govaerts et al. (2008) list 24 species of Tarenna from Thailand in the World Checklist of Rubiaceae. Based on our understanding of species’ patterns of variation and examination of type specimens, our treatment differs from that of the checklist as regards the status of some taxa (see below). In particular, we did not find any specimens of T. asiatica (L.) Kuntze ex K.Schum. from Thailand, which is presented as a Thai species by the checklist. T. asiatica is very similar to T. hoaensis Pit. so some Thai specimens of the latter have been determined as the former in error. T. hoaensis differs from T. asiatica through being a smaller tree with very large leaves and its inflorescences possessing sparsely short-hairy axes.
Gaertn., Fruct. Sem. Pl. 1: 139. 1788; Hiern in Oliver, Fl. Trop. Afr. 3: 88. 1877; Koord. & Valeton, Meded. Lands Plantentuin 59: 77. 1902; Dalla Torre & Harms, Gen. Siph.: 497. 1905; Merr., Philipp. J. Sci. 17: 461. 1920; Pit. in H.Lecomte, Fl. Indo-Chine 3: 205. 1922; Ridl., Fl. Malay Penins. 2: 102. 1923; Hutchinson & Dalziel, Fl. W. Trop.Afr. 2: 75. 1931; Bremekamp in Feddes Repert. Spec. Regni Veg. Nov. 37: 7. 1934; Corner, Ways. Trees. 2: 651. 1940; Backer & Bakh.f., Fl. Java 2: 162. 1965; Bridson, Kew Bull. 34: 377. 1979; Wong in Ng, Tree Fl. Malaya 4: 409. 1989.— Cupi Rheede, Hortus Malabaricus 2: 23. 1678, (nom. rej.);Adans., Fam. Pl. 2: 158. 1791.— Chomelia L, OperaVaria: 210. 1758, (nom. rej.); Schumann in Engl. & Prantl, Pflanzenfam. 4(4): 74. 1891.— ebera Schreb., Gen. Pl. 2: 794. 1791; Benth. & F.Muell., Fl.Austral. 3: 412. 1866; Kurz, Forest Fl. Burma 2: 46. 1877; Hook.f., Fl. Brit. India 3: 101. 1880; King & Gamble, Mat. Fl. Malay Penins. 15: 64. 1904.— Stylocoryna Cav., Icon. 4: 45. 1797; Miq., Fl. Ned. Ind. 2: 202. 1856; King & Gamble, Mat. Fl. Malay Penins. 14: 198. 1904; Ridl., Fl. Malay Penins 2: 108. 1923.— Canthiopsis Seem., Fl.Vit.: 166. 1866.— Bonatia Schltr. & K.Krause, Bot. Jahrb. Syst. 40(92): 44. 1908.— Flemingia Hunter ex Ridl., J. Straits Branch Roy.Asiat. Soc. 53: 83. 1909.— Camptophytum Pierre exA.Chev.,Veg. Ut.Afr. Trop. Franç. 9: 221. 1917.
Small trees, treelets, small or large shrubs, to 7 (–25) m high; young branches subterete to terete in cross-section, with a groove running longitudinally in the middle on the wider sides, bark greenish, brownish or white, glabrous or hairy; older branches terete, subterete to rounded, bark brownish, grey or black, smooth, shallowly cracked or corky, glabrous or pubescent. Leaves simple, opposite-decussate; blade ovate, obovate, elliptic, ovate-oblong, obovate-oblong or lanceolate, membranous to coriaceous; upper surface pale green or greenish, glabrous or sparsely to densely pubescent, hairs often restricted to nerves; lower surface greenish, glabrous or sparsely to densely pubescent, hairs sometimes microscopic, drying dark brown to black; base attenuate, cuneate or rounded; apex acute, acuminate or caudate; margin entire, rarely undulate or sometimes revolute; lateral nerves 4–9(–14) pairs, inconspicuous or conspicuous beneath, without or with hairs tuft or ciliate crypt domatia