Bulbophyllum thydoii

Bulbophyllum thydoii VUONG, Q. T. TRUONG, J. PONERT et J. J. VERM., spec. nov. – sect. Brachyantha RCHB. F. 1861

(Bulbophyllum thydoii Photos Nghiem Xuan Son)

Type: Vietnam, Hon Ba nature reserve, Khánh Hòa province; at 12° 07.037’ N 108° 56.911’ E, about 1 509 m a.s.l.; 20 March 2018, Truong Ba Vuong, Mang Van Lam BV 332 (Holotype VNM!) Description: Clustered epiphyte. Pseudobulbs 1-leafed, glossy, green, brown towards the base, slightly obliquely ovoid, 1.4 – 3.0 cm long, 1.5 – 2.0 cm wide. Leaves dark green, rather thick, narrowly elliptic, 5.5–12cm long, 1.7–2.8cm wide, apex obtuse, slightly retuse; petiole 1.4 – 2.7 cm long. Inflorescence developing together with the vegetative shoot from which it arises (synanthous), subumbellate, with 2 – 10 flowers; peduncle erect, arching at apex, ca. 4.8 – 5,0 cm long, bract 1, tubular, ca. 6 mm long, but the base covered by 2 pale green to reddish, tu- bular, inflated bracts (which are rhizome bracts of the young vegetative shoot from which the inflorescence arises); ra- chis up to c. 3 mm long, not thickened. Flowers wide open, sepals and petals pale yellow, ochre-yellow or pale green, minutely spotted and suffused red except towards the mar- gins, lip yellow, slightly greenish towards apex, suffused red towards the base, column yellow(-green), minutely spot- ted red. Pedicel and ovary 12 – 15 mm long; floral bract ovate, ca. 6 mm long. Dorsal sepal slightly concave, nar- rowly ovate, 15 – 20 mm long, ca. 5 – 8 mm wide, apex obtuse; margins entire; glabrous, 5-veined. Lateral sepals obliquely ovate-triangular, 25 – 29 mm long, 7 – 9 mm wide, apex acute, margins entire, upper margin folded inwards to- wards the apex, the lower margin less distinctly so and only close to the apex, adaxial surface close to the base with a small warty and glossy patch, otherwise glabrous. Pet- als obliquely and broadly elliptic–ovate, 7.0 – 9.0 mm long, 5.0 – 7.0 mm wide, apex subacute, margins entire; glabrous, 5-veined. Labellum fleshy, curved in lateral view, triangular, 6.5 – 7 mm long, 3 – 5 mm wide, slightly tapering towards the apex, apex obtuse, slightly retuse, margins entire; gla- brous, adaxially slightly concave towards the base, slightly convex towards the apex, abaxially with a distinct keel. Col- umn ca. 2 mm long, column foot distinctly elongated so that the petals are not overlapping with the median and lateral sepals towards their base, stelidia short, subulate, with a small, tooth along the upper margin, and deltoid, rounded wing lower down along the lower margin. Anther cap with the anterior margin drawn out into a widely rounded beak. Pollinia 4, the inner pair shorter than the outer.

Ecology and phenology: Epiphyte on trunk or branches, usually associated with Cleisocentron klossii (RIDL.) GARAY, Campanulorchis longipes (GAGNEP.) J. PONERT, Eria lactiflora AVER. and Mycaranthes floribunda (D. DON) S. C. CHEN et J. J. WOOD. Flowering time March until late of March.

Distribution: This species has been so far recorded only from Hon Ba nature reserve in Khánh Hòa province of Vietnam.

Etymology: The specific epithet is to honor Mr. Do Anh THY, forester and director of Hon Ba nature reserve, who feels it is his task in life to protect the forests.