Markhamia Seem. ex Baill., a genus of at least 6 species distributed from tropical Africa and China to Southeast Asia (Mabberley, 2008), can be easily distinguished from other genera in the family by having foliaceous pseudostipules usually present, corolla campanulate-funnel-shaped with dingy yellow to brownish red or reddish yellow to reddish brown, and capsule long cylindric with floccose or villous. Until now, one species of Markhamia has been recorded with two variety M. stipulata var. kerrii and M. stipulata var. pierrei for the flora of Vietnam (Pham, 2000).
During field surveys in Ca Na area, Thuan Nam District of Ninh Thuan Province in southern Vietnam in 2013-2014, the author collected few interesting specimens of Markhamia Seem. ex Baill. They differed significantly from the two Vietnamese variety reported by Pham (2000) and Santisuk & Vidal (1985), and also differed from those from China (Zhang & Santisuk, 1998) and Thailand (Santisuk, 1987). Furthermore, they did not match specimens of Markhamia in the Vietnamese herbaria of VNM and HN nor in the Muséum National d'Histoire Naturelle (P). Hence it is described as a new variety Markhamia stipulata (Wall.) Seem. ex Schum. var. canaense V.S.Dang var. nov.
Markhamia stipulata (Wall.) Seem. ex Schum. var. canaense V.S. Dang
Type: VIETNAM: Ninh Thuan, Thuan Nam District, Ca Na, 30 km southeast of Phan Rang City, alt. 19 m, 11°19'22.32"N 108°48'06.24"E, 20 June 2013, V.S. Dang 210 (Holotype: VNM; Isotypes: VNM, HN, TAI).
The specific epithet is derived from the type locality, Ca Na area of Thuan Nam District in Ninh Thuan Province, Southern Vietnam.
Flowering from April to June, and fruiting from July to September.
Markhamia stipulata var. canaense is known only from a very restricted area of about 20 hectares in Ca Na of Thuan Nam District, Ninh Thuan Province (Southern Viet Nam), at an elevation of about 19-20 m.
This variety occurs in secondary forests, thickets and savannas.
Additional specimen examined:
Vietnam: Ninh Thuan, Thuan Nam District, Ca Na, 30 km southeast of Phan Rang City, alt. 20 m, U°19'23.21"N, 108°48'08.61"E, 18 July 2014, V.S.Dang et al. V1801, and 28 November 2014, V.S.Dang et al. V2256 (VNM!, FU!).
Note: Markhamia stipulata var. canaense is morphologically similar to Markhamia stipulata var. pierrei but differs in having a longer corolla tube, 1114 cm long (vs. 8-10 cm long); shorter capsule, 16-20 cm long (vs. 25-43 cm long); lesser number of leaflets,
6- 9 (vs. 9-13) and lateral veins 5-7 on each side of midrib (vs. 7-9 pairs). It often grows in association with Uvaria micrantha Hook. f. & Thoms., Polyalthia minima Ast., Grewia abutilifolia Vent. ex Juss., Capparis rigida Jacobs, Bauhinia racemosa Lam., Memecylon octocostatum Merr. & Chun., Glochidion hohenackeri (Mull.Arg.) Bedd., Clausena dimidiata Tan., Sauropus poilanei Beille., Koelreuteria paniculata Lamk., Pleiospermum annamense Guill., Tetrastigma pachyphyllum (Hemsl.) Chun, Schefflera canaensis C.B. Shang., Wrightia dubia (Sims) Spreng., Clerodendrum petasites (Lour.) S.Moore.