Nervilia viridiflora Q. Liu & J.W. Li, 2018

Tang, Feng-Xia, Li, Jian-Wu, Pan, Bo, Wu, Xun-Feng, Luo, Yong & Liu, Qiang, 2018, New and Newly Record Orchids of Nervilia (Nervilieae, Epidendroideae, Orchidaceae) in China, Phytotaxa 379 (2), pp. 162-168 : 164

Nervilia viridiflora Q. Liu & J.W. Li , sp. nov. ( Figs 2 , 3 ) ŴAEș±

Type: — CHINA: Yunnan province, Xishuangbanna Dai Autonomous Prefecture, Menglun town, 550 m alt. Menglun, 30 May 2013, Q. Liu 95 (Flowers), and 21 July 2013, Q. Liu 110 (Leaf), (holotype, HITBC!)

Diagnose: — Nervilia viridiflora is similar to N. khaoyaica and N. umphangensis , but can be distinguished from them by having the cordate leaves, greenish flowers and labellum with 2 longitudinal ridges extending from base of lip to apex of mid-lobe.

Tuber ovoid to globose, 10–12 mm in diameter, with irregularly warty on surface. Leaf light green on both surfaces, broadly cordate, 1.8–2.0 × 2.0– 2.2 cm, glabrous, many veined, apex acute or rounded; petiole-like stalk erect, 2.0– 2.4 cm, white, with 1–2`short tubular sheath near base. Inflorescence 7.5–10.5 cm long, 1-flowered; white to green, bearing 2–3 membranous sheathing catephylls 2.1–2.5 cm long; floral bract enclosing the pedicle at base, ovate-lanceolate, 5.0–6.2 × 1.8–2.4 mm, apex acute. Flower erect, opening widely, pedicle and ovary 5.2–6.5 mm long. Sepals and petals purely yellow green or greenish, labellum white with purple spots on the ridges. Sepals similar, elliptic-obovate, 14.2– 18.1 × 2.8–4.3 mm, apex acute; petals lanceolate, 12.7–17.5 × 2.3–3.4 mm, apex acute. Labellum oblong, 10.8–14.0 mm long, spurless, 3-lobed near middle; lateral lobes obovate-flabellate and embracing the column, 4.8–6.8 × 2.8–3.4 mm; mid-lobe orbicular, 6.0–7.2 × 5.2–7.0 mm, margin entire but slightly undulate, emarginate at the apex, densely pubescent-lanate between lateral lobes, with 2 longitudinal ridges extending from base of lip to apex of mid-lobe. Column white, slender, clavate, 4.8–7.3 × 1.3–1.8 mm, with a cluster of hairs below stigma, apex dilated; anther cap transversely elliptic, ca. 2.0 mm in diameter; pollinium enclosed within clinandrium, 2.2–2.8 mm long, stigma shield-shaped; rostellum thickened and protruding. Capsule not seen.

Distribution: — CHINA: Southern Yunnan, Xishuanbannna Dai Autonomous Prefecture, Menglun town.

Habitat: — Terrestrial in the riparian bamboo forest, 550 m alt.

Phenology: — Flowering from May to June, in leaf June to September.

Conservation status: — At present, Nervilia viridiflora is only known from the type site, and this population is estimated to comprise more than 500 mature individuals. However, it is expected that more populations may be found by thorough botanical investigation in the vicinity of the similar forests. Moreover, it is possible that other populations occur in similar habitats in the Laos. Therefore, it is premature to conduct a full conservation assessment based on the one known population. We regard the species as Data Deficient (DD: IUCN 2012).‘

Etymology: — Named for greenish flowers, especially on sepals and petals.

Additionally specimen examined: — CHINA: Yunnan, Menglun , 13 May 2014, Q. Liu 134 (Flower) ( HITBC!) ; Menglun , 21 May 2018, Q. Liu 493 (Flower) ( HITBC!) .

Note:— The characters of one flower/inflorescence and labellum lacking spur indicate that this new species belongs to sect. Linervia. Morphologically, Nervilia viridiflora is similar to N. khaoyaica Suddee, Wattana & S. W. Gale (2013: 333) ( Gale et al. 2013) and N. umphangensis Suddee, Rueangruea and S. W. Gale (2014: 141) ( Gale et al. 2014) by sharing with the characteristic of globose tuber, elliptic-obovate sepals and densely pubescent-lanate between lateral lobes. However, the new species differs from N. khaoyaica by having tuber with irregularly warty surface, cordate leaves, greenish flowers (sepals and petals) and orbicular mid-lobe with two longitudinal ridges extending from base of lip to apex of mid-lobe (tuber with glabrous surface, cordate-polygonal leaves, brownish-beige tinged greenish flowers (sepals and petals) and mid-lobe with a longitudinal ridge extending from the basal third of the lip almost to the apex in N. khaoyaica ); differs from N. umphangensis by having cordate and green leaves, white labellum with purple spots and transversely elliptic anther cap (cordate-polygonal and purple-bronze leaves, purple labellum with white on the longitudinal ridge and helmet-like anther cap in N. umphangensis ).

Figures

FIGURE 2. Nervilia viridiflora.A. Plant with leaf. B. Front view of flower.C. Each part of flower. D. Plant with flower.E. Lateral view of flower. F. Labellum. G. Front and lateral view of column. H. Pollinium.All from the type collection (Q. Liu 95) and drawn by Bo Pan.

FIGURE 3. Nervilia viridiflora. A. Habitat (Leaves). B. Habitat (Flowers). C. Flower. D. Front and lateral view of labellum. E. Plant with leaf. F. Plant with flower. G. Front and lateral view of column. H. Anther cap. I. Clinandrium. J. Abaxial and adaxial pollinium. (Photographed by Q. Liu).