Bulbophyllum truongtamii, 2022

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 : 268-269

8 B. truongtamii Vuong, Aver. & V.S.Dang sp. nov. ( Fig. 5 ).

Type:— Lai Chau Province, Sin Ho District, forest around Sin Ho Town, 24 July 2021, Truong Ba Vuong, Truong Quang Tam, BV 1306 (holotype, VNM00069927 ).

Descriptions: — Epiphytic creeping herb. Pseudobulbs 1-leaved, greenish, narrowly ovoid to fusiform, slightly oblique, 3.2–4.5 cm, tapering to the apex, covered by remnant fibrous sheaths, pseudobulbs well-spaced, connected by semiwoody rhizome, 2.5–7 cm long, 4 mm in diameter, roots from base of pseudobulbs or from nodes of rhizome. Leaves green, petiolate; petiole 2.5–3 cm long; leaf blade narrowly oblong, 10–11 cm long, 2.5–3 cm wide, apex obtuse or retuse. Inflorescence subumbellate, arising from base of pseudobulbs, slender, green with purplish marks; peduncle 20–21 cm long; rachis 1–1.5 mm long, with 5–6 flowers opening simultaneously; floral bract greenish to white with pinkish dots, triangular, 6–7 mm long, acute; pedicel and ovary 9–10 mm long, pedicel slightly upcurved, green, ovary green with pink dots. Median sepal white or pinkish with pink stripes, lateral sepals yellowish or white, pale green at apical part, with pink stripes, petals whitish to pink, with pink stripes, lip white or dark pink. Median sepal broadly ovate, concave, 6–6.6 mm long, 4.5–5 mm wide, margin finely erose or dentate, truncate and mucronate. Lateral sepals 27–29 mm long, 5–6 mm wide, cuspidate, twisted at base, upper margin connate throughout all their length, free at base and along lower margin. Petals narrowly ovate, oblique, falcate 4–5 mm long, 2.5–3 mm wide, ciliate along the margin at basal half, at apex hairy, apex acute with short seta. Lip glabrous, entire, narrowly ovate, simple, curved, 3.5–4 mm long, 2–2.5 mm wide, apex rounded, at base adnate to column foot apex by white appendage; adaxially shallowly channeled at base; abaxially with 2 low keels. Column ca. 2 mm long, with deltoid or rounded wings, stigma obovate, ca. 1.5 mm long; column foot ca. 3.5 mm long; stelidia ca. 0.5 mm long, subulate, acute, pointing forward, upper margin with small triangular tooth; anther cap helmet-shaped, ca. 1 mm long, frontal margin ciliate; pollinia 4, obovate. Fruit not seen.

Habitat and phenology:—Broad-leaved forest. Trunk or branch epiphyte, commonly along streams. Flowering in July.

Distribution: — Vietnam (Lai Chau Province, Sin Ho District). Endemic.

Notes:—The morphological comparison with related species is present on the table.

Figures

FIGURE 5.Bulbophyllum truongtamiiVuong,Aver.V.S.Dang.A.Floweringplant.B.Leafapex,adaxial andabaxial side.C.Inflorescences. D. Floral bract. E. Flowers, frontal and back views. F. Median sepal, adaxial and abaxial side. G. Lateral sepals, adaxial and abaxial side. H. Petals, adaxial and abaxial side. I. Lip, views from different sides. J. Pedicel, ovary and column with sepals removed (above), and with all tepals removed (below). K. Column, frontal view. L. Column, half side 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.