Bulbophyllum strigosum, (Garay) Sieder & Kiehn (2009: 407)

Dang, Minh Quan, Averyanov, Leonid V., Dang, Van Son, Maisak, Tatiana, Bui, Van Huong, Tu, Bao Ngan & Truong, Ba Vuong, 2022, Bulbophyllum section Rhytionanthos (Orchidaceae) in Vietnam with description of new taxa and new national record, Phytotaxa 530 (3), pp. 257-270 : 266

5. B. strigosum (Garay) Sieder & Kiehn (2009: 407) ( Fig. 2 ).

≡ Rhytionanthos strigosum Garay (1999: 311) .

Type:— VIETNAM, N Vietnam without indication of locality, ex Hort. Botanical Garden of the University of Vienna , Anton Sider 250/92, holotype: WU0063106 https://www.jacq.org/detail.php? ID =267211 photo!; isotype AMES00084913 not seen .

Description:—Epiphytic creeping herb. Pseudobulbs 1-leaved, pale green, narrowly ovoid, oblique, 2–2.5 cm tall, tapering to the apex, growing close together, connected by semi-woody rhizome, 2.3–2.5 mm in diameter, young pseudobulbs covered by brown fibrous sheaths. Leaves green, slightly twisted, petiolate; petiole 2.3–3.7 cm long; leaf blade narrowly oblong, 10–13 cm long, 1.8–2.2 cm wide, obtuse, slightly unequally 2-lobed. Inflorescence subumbellate, arising from base of pseudobulbs, erect, slender, green, spotted with purple; peduncle ca. 14.5 cm long with 1 to 2 overlapping tubular bracts at base and 2 distant tubular bracts above; rachis 1.5–2 mm long, bears 4–5 flowers opening simultaneously; floral bracts 6–8 mm long; pedicel and ovary ca. 1.5 cm long, slightly curved. Flower pale yellow with many red dots, more dense on lateral sepals and less in median sepal, petals yellow, margin dark red, lip adaxially dark red mottled with white, adaxially with many red blotches. Median sepal narrowly ovate to ovate, concave, ca. 9 mm long, 4 mm wide, obtuse, margin shortly fimbriate; lateral sepals ca. 2.5 cm long, 4 mm wide (at base) apex cuspidate, upper and lower margin sparsely papillose, outer surface sparely proximally verrucose; twisted and free at base, upper and lower margin turning inward and connate from near base to apex, distally forming narrowing tube. Petals ovate, ca. 2.5 mm long, 2 mm wide, margin fimbriate, apex obtuse. Lip mobile, with white thin ligament connected with apex of column foot, simple, recurved, ligulate, ca. 5 mm long, ca. 1.7 mm wide, apex obtuse to rounded; margin densely papillose; at base adaxially grooved. Column ca. 2 mm tall, at front with triangular wings, column foot ca. 3 mm long, upcurved; stelidia slender, subulate, ca. 6 mm long, slightly upcurved, upper margin with truncate tooth, lower margin sometime finely erose; anther cap rectangular in outline, ca. 1.2 mm long, with umbo at apex; pollinia 4, obovate, ca. 0.8 mm long. Fruit not seen.

Habitat and phenology:—Evergreen broad-leaved forests at elevation about 1000 m a.s.l., rare. Branch epiphyte. Flowers at the end of May.

Distribution:— Vietnam (Lai Chau Province). Endemic.

Notes:—The specimens were found and collected in Sin Ho District, Lai Chau Province, and later were cultivated in private garden in Da Lat Town. Fimbriate median sepal, lateral sepals turning inwards with adnate upper and lower margins, shortly fimbriate free part of upper margin, fimbriate petals, and densely papillose lip are key characters of this species.

Studied specimen:— VIETNAM, herbarium specimens prepared on 30 May 2021 by Truong Ba Vuong, Dang Van Son, Nghiem Xuan Son, BV 1255 ( VNM00069914 ), BV 1256 ( VNM00069915 ) from plants cultivated in Lam Dong Province, Da Lat Town, originated from Lai Chau Province, Sin Ho District, forest around Sin Ho Town .

Figures

FIGURE 2. Bulbophyllum strigosum Garay. A. Flowering plant. B. Inflorescences. C. Floral bract. D. Flowers, half side, side, and back views. E. Median sepal, adaxial and abaxial side. F. Median sepal margin. G. Lateral sepals, adaxial and abaxial sides. H. Lateral sepal margin. I. Petals, adaxial and abaxial side. J. Lip, views from different sides. K. Pedicel, ovary and column, side view. L. Column, frontal and side views. M.Anther cap, views from different sides. N. Pollinia. Photos by Truong Ba Vuong, correction and design by L.Averyanov and T. Maisak.