Begonia adscendens C.B. Clarke (1890: 26)

Bon, Trinh Ngoc, Do, Thi Thanh Ha, Le, Thi Hanh, Lo, Minh Duc, Zimmer, Heidi & Lin, Che- Wei, 2023, Begonia saxifragoides sp. nov. and two new records of Begonia (Begoniaceae) from northern Vietnam, Phytotaxa 600 (1), pp. 16-24 : 22

Begonia adscendens C.B. Clarke (1890: 26) .

Type:— INDIA. Nagaland: Naga Hills, Jakpho , ix 1937, C. B. Clarke 41240 (lectotype K [ K000634623 ]) .

Distribution and ecology:— Begonia adscendens is a relatively widespread species from northeastern India to Myanmar and Laos, where it is epiphytic on cliffs or rocks in montane cloud forests. In Vietnam, it grows on nearly vertical rock faces from the cliff base in semi-shaded areas at 2,000 –2,200 m elevation in Ngoc Chien Commune, Muong La District, Son La Province ( Fig. 1 ).

It can be easily distinguished from other Vietnamese tuberous begonias by having glabrous petioles and peduncles, sub-asymmetric lamina with a glabrous adaxial surface, 4-tepaled staminate flowers and 5-tepaled pistillate flowers, outer tepals sparsely pale puberulous on reverse, ovary 3-locular with bifid placentation, abaxial wing reaching up past the apex of the fruit capsule.

Specimen examined:— VIETNAM. Son La Province: Muong La District, Ngoc Chien Commune , 2,100 m elevation, 17 September 2022, Trinh Ngoc Bon, Thi Thanh Ha Do, Thi Hanh Le, Minh Duc Lo, Heidi Zimmer, Lo Van Chieu, Sung A Giang & Sung A Chu SCU2022-02 ( VAFS) .

Figures

FIGURE 1. Distribution map of Begonia saxifragoides (yellow star), B. minhaniae (blue circle), B. adscendens and B. laotica (red triangular) in northern Vietnam.