Oreorchis yachangensis Z.B.Zhang & B.G.Huang, 2016

Zhang, Zibin, Xin, Rongshi, Qin, Suhuai, Huang, Bogao, Wei, Xinlian & Liu, Yan, 2016, Oreorchis yachangensis (Orchidaceae), a new species from Guangxi, China, Phytotaxa 265 (2), pp. 169-172 : 169-172

Oreorchis yachangensis Z.B.Zhang & B.G.Huang , sp. nov. ( Figs. 1 & 2 )

Type: — CHINA. Guangxi: Leye County, Yachang Orchid National Nature Reserve, alt. ca. 1,685 m, 23 May 2015, S. W.Li, Z. C.Lu, J.Liu, Z. B.Zhang & R. S. Xin YC2190 (holotype IBK!, isotype PE!).

Plants terrestrial, up to 30–45 cm tall. Pseudobulb ovoid to sub-ellipsoid, 1–2 × 0.5–1.5 cm, 2- or 3-noded. Leaf solitary, or rarely 2, petiolate, plicate, linear or narrowly lanceolate, up to 35 cm long and 2.7 cm wide, apex acuminate; petiole up to 3.8 cm long. Scape arising from side of pseudobulb, green, enclosed by tubular sheaths; sheaths up to 4 cm long. Inflorescence 25–67 cm, loosely up to 20-flowered, racemose; Flowers small, up to 9.4 mm long and 6.3 mm wide; ovary 6–9 mm; dorsal sepal yellow, narrowly oblong, apex slightly obtuse, up to 6.5 mm long and 1.7 mm wide; lateral sepals slightly falcate, elliptic-lanceolate, acute, yellow, up to 6.2 mm long and 1.6 mm wide; petals yellow, narrowly oblong, slightly falcate, apex acute, up to 4.5 mm long and 1.1 mm wide; lip oblong, with purple spots, up to 3.8 mm long and 1.9 mm wide when spread, shortly clawed at base, 3-lobed below middle; lateral lobes slightly incurved, apex obtuse; mid-lobe nearly oblong, apex 2- lobed, irregularly incised; disk with a pair of thick lamellae, extending from base to midway along mid-lobe; column white, clavate, up to 3.2 mm long, base thickened; anthers apical; stipe hamular, J-shaped.

Distribution: Only one population of the new species has been found in the Panguwang River valley, Leye County, Yachang Orchid National Nature Reserve, western Guangxi, China.

Phenology: The new species was observed in flowering occurs from May to June, and fruiting from August to September.

Habitat and ecology: The new species occurs in primary subtropical deciduous broadleaf forest, elevation from ca. 1650–1690 m. The main trees of tree layer are Betula alnoides Buch. -Ham. ex Don (1825: 58), Quercus variabilis Blume (1850: 297) and Alniphyllum fortunei ( Hemsley 1889: 173) Makino (1906: 93) . The new species is sympatric with Goodyera biflora (Lindley 1840: 496) Hooker (1894: 114) and Calanthe mannii Hooker (1890: 850) .

Etymology: The species is named after the type locality, Yachang Orchid National Nature Reserve, Leye County, Guangxi, China.

Similar species: — Oreorchis yachangensis is similar to O. patens , but differs from it by having small flowers, yellow sepals and petals, petals and the lip with purple spots. It also can be distinguished other species of genus Oreorchis by 2-lobed at the mid-lobe apex of lip. The diagnostic characters of the new species and its similar species are listed in TABLE 1.

Figures

FIGURE 1. Oreorchis yachangensis. A. Habit. B. Flower in front view. C. Bract. D. Flower form. 1. Ovary and stigma. 2. Lip. 3. Lateral sepal. 4. Petal. 5. Dorsal sepal.

FIGURE 2. Oreorchis yachangensis: A. Habit. B. Roots and tubers. C. Flower form. D. Bract. E. Lip in front view. F. Flower in side view. G. Raceme. H. Flower in back view. I. Flower in front view. J. Stigma in front view (Pollinaria). K. Stigma in side view.