Bulbophyllum taeniophyllum var. denticulatoalatum, 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 : 267-268

7.2. B. taeniophyllum var. denticulatoalatum Vuong & Aver. var. nov. ( Fig 3 and Fig 4 G & H ).

Type:— VIETNAM, holotype specimen prepared on 29 April 2021 by Truong Ba Vuong, Phan Trong Quyet, BV 1160 ( VNM00069901 , LE01122221 http://en.herbariumle.ru/?t=occ&id=82694 photos) from cultivated plant obtained from a private garden in Da Lat Town, Lam Dong Province, originated from Ha Giang Province, Quan Ba District , Quyet Tien Commune , Lung Muoi Moutain .

Etymology. The epithet refers to the denticulate lower margin of column wings.

Description:—Epiphytic creeping herb. Pseudobulbs 1-leaved, green, dark green near apex and chestnut at base, clustering, ovoid to narrowly ovoid, oblique or straight, 1.2–3.3 cm tall. Leaves petiolate; petiole 0.6–2 cm long, usually twisted at base; leaf blade adaxially green, abaxially green or occasionally purple, oblong to narrowly oblong, 5.5–14.5 cm long, 1.5–2.1 cm wide, obtuse, slightly retuse. Inflorescence umbellate to subumbellate raceme; peduncle glabrous, purple or green, spotted with purple, slender, arising from base of pseudobulbs, 8–15 cm long, with 1 to 3 distant tubular bracts; rachis 1–5 mm long, with 2–13 flowers opening simultaneously; floral bracts glabrous, 4–5.5 mm long; pedicel and ovary glabrous, 1–1.4 cm long, ovary with 6 prominent ridges. Flower brownish-yellow to brown, tepals adaxially with red streaks, abaxially with small red dots, lip red above, yellowish below. Median sepal ovate, concave, 7.5–9 mm long, 4–5 mm wide, with 5 veins, acute, margin sparsely ciliate; lateral sepals glabrous, narrowly ovate, slightly falcate, 16–18 mm long, 4–5 mm wide, concave, twisted at base, upper and lower margin free at base, turning inward and connate from near base to apex, forming a fusiform tube, tapering to acute apex. Petals narrowly ovate, oblique, with 3 veins, acute, margin fimbriate on apical half. Lip mobile, with white thin ligament connected with column foot apex, simple, slightly, recurved, ligulate, glabrous, ca. 4 mm long, 1.3 mm wide, apex obtuse, grooved at base, abaxially with 2 low keels. Column ca. 2 mm tall, at front with small triangular wing; column foot upcurved, ca. 2.5 mm long; stelidia subulate, acute, slightly falcate, upper margin with an erect acute tooth, lower margin denticulate; anther cap glabrous, ca. 1 mm long and wide, above with a yellow umbo; pollinia 4, ovoid. Fruit not seen.

Habitat and phenology:—Epiphyte on large trees at elevation about 1200 m a.s.l. Not common. Flowers in April–May.

Distribution:— Vietnam (Bac Kan, Ha Giang, Hoa Binh, Lam Dong, and Ninh Binh provinces).

Notes:—The new variety differs from B. taeniophyllum var. taeniophyllum mainly in denticulate column wings. Its morphological comparison with related taxa are presented in table. In addition, there are 3 different forms of this variety which differ in the shape of lateral sepals and the arrangements of flowers on rachis ( Fig. 4 . A-F).

Studied specimens (paratypes):— VIETNAM, Bac Kan Province, Cho Don District, Ban Thi Municipality, Phia Khao Village, around point 22º17’31’’N, 105º31’51’’E, Cau Muc Mountain at elevation of around 800–900 m a.s.l., primary broad-leaved evergreen closed forest on very steep slopes and cliffs near tops of rocky ridge composed with solid marble-like stratified limestone, epiphyte, leaves below with light purple-violet tint, not common, 24 May 2004, L. Averyanov et al., HAL 4859a ( LE 01057942 http://en.herbariumle.ru/?t=occ&id=8445, LE 01087453 http:// en.herbariumle.ru/?t=occ&id=38856 photos). VIETNAM, Bac Kan Province, Cho Don District, June 2017, C.X.Canh s.n. ( LE 01087697 http://en.herbariumle.ru/?t=occ&id=42919 photos). VIETNAM, herbarium specimen is prepared on 30 April 2021 by Truong Ba Vuong, Phan Trong Quyet, BV 1156 ( VNM 00069904, LE 01122220 http://en.herbariumle. ru/?t=occ&id=82693 photos) from plants cultivated in private garden in Da Lat Town, originated from Ha Giang Province, Quan Ba District, Quyet Tien Commune, forest around Tan Tien Village. VIETNAM, Hoa Binh Province, Lac Son District, Ngoc Son Municipality, Khu Village, Bua Coi Mt., around point 20°27′10″N 105°18′52″E, in heavily logged closed primary evergreen broad-leaved forest on top ridges of limestone mountains at elevation of around 700– 790 m a.s.l., 29 March 2011, N. Q.Hieu et al., CPC 1734a ( LE 01057936 http://en.herbariumle.ru/?t=occ&id=8441, LE 01087455 http://en.herbariumle.ru/?t=occ&id=39090 photos). VIETNAM, herbarium specimen is prepared on 30 April 2021 by Truong Ba Vuong, Phan Trong Quyet, Ngo Quang Dang, BV 1155 ( VNM 00069903, LE 01122219 http://en.herbariumle.ru/?t=occ&id=82692 photos) from plant cultivated in private garden in Da Lat Town, originated from Lai Chau Province, Sin Ho District. VIETNAM, Lam Dong Province, Da Lat Town, Hang Cop Stream, 12 May 2021, Truong Ba Vuong, Phan Trong Quyet, BV 1171 ( VNM 00069902). VIETNAM, Ninh Binh Province, Cuc Phuong National Park, a. 1985, L. Averyanov, LX-VN s.n. ( LE 01057945 http://en.herbariumle.ru/?t=occ&id=15158, LE 01087456 http://en.herbariumle.ru/?t=occ&id=39132 photos). VIETNAM, Ninh Binh Province, Cuc Phuong National Park, 2002, Averyanov s.n. ( LE 01087381 http://en.herbariumle.ru/?t=occ&id=38701 photos).

Figures

FIGURE 3. Bulbophyllum taeniophyllum var. denticulatoalatum Vuong & Aver. A. Flowering plant. B. Pseudobulbs. C. Pseudobulb and leaf, adaxial side. D.Abaxial leaf surface. E. Inflorescence.F. Flowers, frontal view. G. Flowers, half side and side views.H. Median sepal, adaxial and abaxial side. I. Lateral sepals, adaxial and abaxial side. J. Petals, adaxial and abaxial side. K. Lip, views from different sides. L. Ovary, column, and lip, side view. M. Pedicel, ovary and column, side view. N. Column, frontal and side views. O. Anther cap, views from different sides. P. Pollinia. Photos by Truong Ba Vuong, correction and design by L. Averyanov and T. Maisak.

FIGURE 4. Four observed forms of Bulbophyllum taeniophyllum var. denticulatoalatum Vuong & Aver. A, B [BV 1156 (VNM)], C, D [BV 1155 (VNM)], E, F [BV 1171 (VNM)], G,H [BV 1160 (VNM)].All photos by Truong Ba Vuong.