Bulbophyllum sect. Minutissima

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 : 14

Bulbophyllum sect. Minutissima

Bulbophyllum mucronatum (Blume) Lindley (1830: 50) , Backer & Bakhuizen van den Brink (1968: 391), Comber (1990: 267), Vermeulen et al. (2015: 674), Schuiteman et al. (2022: 128).

( Fig. 7 )

≡ Diphyes mucronata Blume (1825: 317) .

Type:— INDONESIA. Java, [West Java Province,] Mont Pancar, Blume 1926 (lectotype, designated here: L L 0058228 photo!, isolectotypes L L 0058226 photo!, L 0058227 photo!).

= Bulbophyllum nanopetalum Seidenfaden (1979: 60) . Averyanov et al. (2018a: 28). Type: — THAILAND. [Kanchanaburi Province:] Kanburi, Thawng Phaphum, 300 m, February 1962, GT 4284, flowered under cultivation and dried in March 1983 (holotype C C10016161 photo!).

Habitat and phenology in Vietnam: —Creeping epiphyte. Submontane broad-leaved evergreen forests at elevation of 1000–1500 m a.s.l. Rare?. Flowers in December–January.

Distribution: — Vietnam: Son La Province (Thuan Chau District). Bhutan?, Thailand, Laos, Cambodia, Peninsular Malaysia, Sumatra, Java, Borneo, Sulawesi, the Philippines.

Conservation status in Vietnam: —Comprehensive conservation assessment of Bulbophyllum mucronatum is complicated by the scarcity of information about its distribution and population characteristics. At the same time, the intensive deforestation in its expected distribution area in Vietnam implies that the species is to be considered as nationally Near Threatened (NT).

Notes: —In the original description of Diphyes mucronata, Blume (1825) did not cite any particular collections, but indicated the place of species origin as “in montanis Pantjar”. Pantjar Mountain in West Java is alternatively spelled as Pancar. Vermeulen et al. (2015) stated the specimen Blume 1926 from Pancar housed at L to be a type of this species (which does not fulfill the conditions of lectotypification according to Arts. 7.11 and 9.23 of ICN, Turland et al. 2018). We found three sheets belonging to the gathering Blume 1926, all of which closely meet the information given in the protologue. These three sheets are deposited at L. We selected the specimen L0058228 as the lectotype following Arts. 9.3 and 9.11 of ICN as it represents best the species. The specimens L0058226 and L0058227 are isolectotypes.

Bulbophyllum mucronatum is reported here as a new record for the flora of Vietnam. The discovery of this species in Vietnam was rather expectable, given its general wide distribution in Indochina and Malesia, including the recent findings from Laos ( Averyanov et al. 2018a) and Cambodia ( Schuiteman et al. 2022). The record of this species in Bhutan ( Gyeltshen et al. 2021) remains questionable, because it is not supported by voucher herbarium specimens.

Bulbophyllum mucronatum is very similar morphologically to B. nematocaulon Ridley (1920: 197 ; see also Vermeulen 1991, Averyanov 2010, Vermeulen et al. 2015, Ya et al. 2021), but differs from the latter in closely arranged (vs. rather distant) pseudobulbs, long acuminate sepals (vs. sepals narrowly triangular to shortly acuminate), lip oblong with roundish apex (vs. lip cordate with obtuse to acute apex), and very short, indistinct stelidia 0.1–0.3 mm long (vs. stelidia distinct, 0.4–0.6 mm long).

Studied specimens:— VIETNAM. Son La Province: Thuan Chau District, forest around Pha Din Pass, creeping epiphyte, 12 January 2023, Truong Ba Vuong BV 1843 (VNM 00070005, photos LE LE01123789 https://en.herbariumle. ru/?t=occ&id=160182).

Figures

FIGURE 7. Bulbophyllum mucronatum. A–C. Flowering plant. D. Flattened flowering plant. E. Flower, front and side views. F. Median sepal, abaxial side. G. Lateral sepals, abaxial side. H. Petals, adaxial and abaxial side. I. Lip, views from different sides. J. Pedicel, ovary, petal, lip and column, side view. K. Pedicel, ovary, lip and column, view from above. L, M. Pedicel, ovary, lip and column, side view. N. Ovary, column and column foot. Photos by Truong Ba Vuong from living plant prior to the preparation of the voucher herbarium specimen Truong Ba Vuong BV1843. Photo correction and design by L. Averyanov and T. Maisak.