Bulbophyllum sect. Stachysanthes

Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Nuraliev, Maxim S., Nguyen, Khang Sinh, Maisak, Tatiana V., Yudova, Daria A., Saidov, Nikita T., Nguyen, Cuong Huu & Nong, Duy Van, 2024, New orchids in the flora of Vietnam VIII (Orchidaceae: Epidendroideae, tribes Malaxideae, Neottieae and Podochileae), Phytotaxa 658 (1), pp. 1-49 : 18-20

Bulbophyllum sect. Stachysanthes (= B. sect. Aphanobulbon pro parte)

Bulbophyllum gibbosum (Blume) Lindley (1830: 54) , Holttum (1964: 448), Backer & Bakhuizen van den Brink (1968: 379), Comber (1990: 291, 2001: 727), Vermeulen (1991: 57), Seidenfaden & Wood (1992: 463), Wood & Cribb (1994: 292), O’Byrne (2001: 28), Vermeulen et al. (2015: 386).

( Fig. 9 )

≡ Diphyes gibbosa Blume (1825: 312) .

Type: — INDONESIA. West Java Province: in sylvis altioribus montis Salak, Blume 1973 HLB 902, 322-417 (holotype L, fide Vermeulen 1991, Wood & Cribb 1994 and Vermeulen et al. 2015).

Habitat and phenology in Vietnam: —Creeping epiphyte. Primary and old secondary evergreen broad-leaved and mixed forests on granite at elevations of about 1500 m a.s.l. Rare?. Flowers in July–August.

Distribution: — Vietnam: provinces Son La (Thuan Chau District) and Lam Dong (Lac Duong District). Peninsular Malaysia, Sumatra, Java, Borneo, Lesser Sunda Islands.

Conservation status in Vietnam: — Bulbophyllum gibbosum is known within the country from not more than three locations, mainly from severely disturbed areas. Since further studies are needed for clarification of the characteristics of its populations, we estimate the national conservation status of the species as Data Deficient (DD).

Notes: — Bulbophyllum gibbosum is reported here as a new record for the flora of Vietnam. The discoveries reported here essentially expand the known distribution area of this species to the north, since it was earlier believed to be a Malesian endemic. The species is morphologically very similar to B. apodum Hooker (1890: 766; see also Holttum 1964, Seidenfaden 1979, Vermeulen 1991, Seidenfaden & Wood 1992, Comber 2001, Chen et al. 2009, Vermeulen et al. 2015, Jin et al. 2023), but differs from the latter in dense inflorescence arising on the rhizome close to the leaf and being enveloped together with the leaf petiole by common sheath-like bracts (vs. inflorescence rather lax, arising away from the leaf, breaking through the sheath-like bracts or pushing them wide apart), sepals usually shortly acuminate (vs. acute to caudate), and large prominent callus below stigma (vs. callus below stigma usually rather insignificant).

Studied specimens:— VIETNAM. N Vietnam, sine loc., fl. in culture, 16 February 2004, L. Averyanov et al., HAL s.n. (photos LE LE01073427 https://en.herbariumle.ru/?t=occ&id=17251). VIETNAM. Son La Province: Thuan Chau District, Phong Lai Commune, Phieng Long Village, Pha Din Pass area, remnants of primary evergreen broad-leaved forests on limestone mountains, elevation of 800–1000 m a.s.l., lithophytic or epiphytic, flowers yellowish white, with yellow lip, not rare, 5 July 2023, K.S. Nguyen, T.V. Lo, AL2229 (photos LE LE01124253 https://en.herbariumle. ru/?t=occ&id=180603). VIETNAM. Lam Dong Province: Lac Duong District, forest around Klong Klanh Village, 10 August 2018, Truong Ba Vuong, Ngo Quang Dang, BV 525 (VNM 00070003, photos LE LE01123804 https:// en.herbariumle.ru/?t=occ&id=163667).

Figures

FIGURE 9. Bulbophyllum gibbosum. A.Flowering plant.B. Shoot with young leaf.C. Leaf apex, adaxial side.D. Portionof inflorescence. E. Flowers on rachis. F. Flower, side view. G. Flower, side view (lateral sepal removed). H. Flower, side view (median and lateral sepals removed). I. Flattened flower, front view (lip removed). J. Median sepal. K. Petal. L. Lateral sepal. M. Lip, views from different sides. N. Ovary, column and column foot, side view. O. Column and column foot, half-side view. P. Column, front view. Q. Pollinia. Photos by Khang Sinh Nguyen from the specimen K.S. Nguyen, T.V. Lo, AL2229. Photo correction and design by L. Averyanov and T. Maisak.