Bulbophyllum ignevenosum Carr (1930: 130)

Dang, Minh Quan, Averyanov, Leonid V., Maisak, Tatiana V., Tran, Thi Thuy Nhan, Nguyen, Van Canh, Wook, Um Sung, Nguyen, Quoc Bao, Truong, Quang Tam & Truong, Ba Vuong, 2024, Bulbophyllum section Macrocaulia (Orchidaceae) in Vietnam, Phytotaxa 677 (3), pp. 265-277 : 269-272

5. Bulbophyllum ignevenosum Carr (1930: 130) , Holtum (1964:435), Seidenfaden & Wood (1992: 512).

( Figs. 1E , 2 & 3 )

Type: — MALAYSIA. Gunung Tahan, Carr s.n. ( SING?).

Description (based on Vietnamese specimens).—Miniature branch epiphyte with creeping rhizome. Pseudobulbs 1- leaved, elliptic, broadly elliptic, or oblong, oblique, 2–6 mm long, grow in form of chain. Leaves with very short petiole, ca. 1 mm long, leaf blade elliptic, oblong to narrowly obovate, 8–13 mm long, 2–5 mm wide, apex rounded, finely mucronate. Inflorescence 1-flowered, arising from the base of pseudobulbs; peduncle up to 16 mm long, glabrous, slender, at base with 3 tubular bracts; floral bract tubular, ca. 1.5 mm long, pedicel and ovary 9–11 mm long. Flowers widely opening, sepals and petals orange with dark orange veins, lip red, distally orange or yellow. Sepals and petals surface smooth with entire margin. Median sepal ovate to narrowly ovate, 4–7.5 mm long, 1.8–2 mm wide, apex acute, 3-veined (lateral veins forked). Lateral sepals ovate to broadly ovate, 5–10 mm long, 3–4 mm wide, apex acute, 5-veined. Petals oblong, ca. 2 mm long, ca. 0.5 mm wide, apex obtuse, 1-veined. Lip entire, simple, glabrous, glossy, triangular in outline shape, ca. 3 mm long, ca. 1 mm wide, attached to column foot by small white appendage, apex obtuse; margins at basal third erect forming a channel (triangular at cross section); at apical part of lip the margin fold down. Column erect, ca. 0.6 mm tall, column foot ca. 1–1.5 mm long, distally up curved; stelidia subulate, slightly curved, pointing forward, ca. 1.2 mm long, lower margin with inconspicuous rounded wing; stigma round; anther cap yellowish, helmet-shaped; pollinia 2. Fruit not seen.

Habitat and phenology: —Creeping branch and canopy epiphyte. Broad-leaved evergreen forests at elevations of 1200–1500 m a.s.l. Flowers in May–October.

Distribution: — Vietnam (provinces Dak Nong, Lam Dong, and Khanh Hoa). Malaysia.

Conservation assessment:— Bulbophyllum ignevenosum has an extent of occurrence (EOO) of approximately 5749 km ² and an area of occupancy (AOO) of about 20 km ². It is found in Dak Nong, Lam Dong, and Khanh Hoa provinces in Vietnam, with a higher concentration in Lam Dong Province. The species is heavily targeted by illegal collectors, especially in Lam Dong Province, where its population is threatened by the removal of both the orchid and the host trees on which it grows. These activities not only damage the orchid population but also lead to habitat degradation by cutting down trees that support other plant species. Hence, four sites of occurrence of this species are considered as four locations. Based on above information this species can be assessedin Vietnam as Endangered [EN B2ab(iii,v)]. This species was originally reported from Peninsular Malaysia ( POWO 2024) showing a very disjunct distribution in Vietnam.

Note: —Some specimens belonging to the studied section and collected recently in southern Vietnam in provinces Khanh Hoa, Lam Dong, and Dak Nong were misidentified as B. moniliforme , or B. menghaiense Tsi (1982: 109) . Detailed study of these specimens indicates their identity as B. ignevenosum having very similar subulate stelidia and large stigma shown by Carr for type material (1932, Plate 1, fig. 6a, h). These identifications presently confirm the presence of B. ignevenosum in Vietnam by voucher specimens and analytical photographs.

Seidenfaden (1979) noted that specimens of Pollane (Poilane 21953 MNHN-P-P0034813, http://coldb.mnhn. fr/catalognumber/mnhn/p/p00348136 and Poilane 22300 MNHN-P-P00348137, http://coldb.mnhn.fr/catalognumber/ mnhn/p/p00348137) looks very much like B. moniliforme , but have oblique pseudobulbs flowering with leaves. These features fit well with characters of B. ignevenosum . Hence, they may represent this species in our opinion.

Detailed descriptions of B. ingevenosum based on specimens firstly confirmed for Vietnam is presented above.

Specimen examined: — VIETNAM: Dak Nong Province: Dak Song District, Nam Nung Protected Area, dry evergreen broad-leaved submontane forest on basalt and sandstone at elevation of 800–900 m a.s.l., epiphyte on tall tree, occasional, 25 October 2019, L. Averyanov, Nguyen Van Canh, T. Maisak, AL1183.1 (LE LE01068472 https://en.herbariumle.ru/?t=occ&id=8439). VIETNAM, Lam Dong Province: Bao Loc District, 11 November, 2021, L. Averyanov, Nguyen Van Canh, Truong Ba Vuong, T. Maisak, AL2572 (LE LE01253783 https://en.herbariumle. ru/?t=occ&id=8439). VIETNAM, Lam Dong Province: Bao Lam District, B’La Commune, 13 June 2023, Truong Ba Vuong BV1794 (VNM VNM00063960 photos LE LE01255201 https://en.herbariumle.ru/?t=occ&id=238727). VIETNAM, Khanh Hoa Province: Khanh Le Pass, secondary open forest on shale at elevation of 700–800 m a.s.l., adpressed epiphyte on bole of big tree in shady places along rocky stream, occasional, 13 May 2024, L. Averyanov, Nguyen Van Canh, T. Maisak, AL3228 (LE LE01255175 https://en.herbariumle.ru/?t=occ&id=234685).

Figures

FIGURE 1. Flowers of species of Bulbophyllum section Macrocaulia in the flora of Vietnam. A. Bulbophyllum ovalifolium (specimen BV378 VNM00070770). B. B. malleolabrum (AL3183 LE01255063). C. B. catenarium (BV1210 VNM00070774). D. B. moniliforme (BV s.n. LE 01087378. E. B. ignevenosum (BV1794 VNM 00063960). F. B. physocoryphum (BV1041 VNM00070762). Photos by Truong Ba Vuong and L. Averyanov.

FIGURE 2. Bulbophyllum ignevenosum. A. Flowering plants. B. Peduncle and flower, side view. C. Flowers, view from different sides. D. Median sepal, adaxial and abaxial side. E. Lateral sepals, adaxial and abaxial side. F. Petals, adaxial and abaxial side. G. Lip, views from different sides. H. Apical part of peduncle, pedicel, ovary and column, side view. I. Column, half-side view. J. Column, front view. K. Column, side view. L. Pollinaria. Photos by Truong Ba Vuong from specimen BV1794, photo-correction and design by L. Averyanov and T. Maisak.

FIGURE 3. Bulbophyllum ignevenosum. Flowering plants in natural habitat. Photos by Nguyen Van Canh sine num. Nam Nung Nature Reserve, 19 July 2023.