Dendrobium sect. Calcarifera

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 : 20

Dendrobium sect. Calcarifera

Dendrobium lampongense Smith (1908: 14) , Seidenfaden & Wood (1992: 381), Wood & Cribb (1994: 254), Seidenfaden (1997: 36), Comber (2001: 610), Wood (2014: 374), Teoh (2021: 310).

( Fig. 10A )

Type: — INDONESIA. Sumatra: Lampung Province, D. Brautigam s.n. (holotype BO, fide Wood & Cribb 1994).

Habitat and phenology in Vietnam: —Clustering epiphyte. Primary and old secondary lowland broad-leaved evergreen forests. Very rare. Flowers in October–December (under cultivation).

Distribution: — Vietnam: provinces Dak Lak (sine loc.) and Lam Dong (Bao Loc District). Peninsular Thailand, Peninsular Malaysia, Sumatra, Borneo.

Conservation status in Vietnam: —Two available Vietnamese records of this remarkable species are based on cultivated wild collected plants originated from Dak Lak and Lam Dong provinces ; their exact locations remain unknown, however, the area of occupancy is inferred as <10 km 2. The species is a typical element of lowland primary forests, which are being dramatically destroyed almost everywhere in southern Vietnam. Taking into consideration the very small area of occupation, decreasing area and quality of habitats, as well as severe plant exploitation, we estimate the national conservation status of this species as Critically Endangered ( CR) on the basis of the following criteria: B2 ab(i,ii,iii). The conservation status of this species outside Vietnam has never been evaluated .

Notes: — Dendrobium lampongense was earlier believed to have predominantly Malesian distribution. The discoveries reported here essentially expand its known distribution area, being its first known localities in Eastern Indochina.Throughout its distribution range, this nice-flowering species is very rare. It is widely collected for cultivation as an ornamental plant. As a result, it probably stands on the verge of full extinction in nature in a significant portion of its modern distribution area.

Studied specimens:— VIETNAM. Dak Lak Province: wild collected plant cultivated in private garden of B.Q. Viet, photos made on 19 October 2017, L. Averyanov, T. Maisak, AL2814 (photos LE LE01088698 https:// en.herbariumle.ru/?t=occ&id=57917). VIETNAM. Lam Dong Province: wild collected plant originated from Bao Loc District, cultivated in private garden of Hoang Thai Ha, photos made on 28 November 2015, L. Averyanov, T. Maisak, AL2813 (photos LE LE01088699 https://en.herbariumle.ru/?t=occ&id=57918).

Figures

FIGURE 10. A. Dendrobium lampongense. Photo by L. Averyanov from the specimen L. Averyanov, T. Maisak, AL2814. B–D. Dendrobium densiflorum. Photos by L. Averyanov from the specimen L. Averyanov et al., VR1800. E, F. Dendrobium nobile var. luteoalbum. Photos by L. Averyanov from living plant prior to the preparation of the type herbarium specimen L. Averyanov et al., LX- VN2107. G–I. Dendrobium polyanthum. Photos by L. Averyanov from the specimen L. Averyanov, T. Maisak, AL2816. Photo correction and design by L. Averyanov.