Platanthera zijinensis Q.L. Ye, Z.M. Zhong & M.H. Li, 2018

Ye, Qin-Liang, Li, Yu-Feng, Zhong, Zhi-Ming, Wu, Lin-Fang, Chen, Li-Jun & Li, Ming-He, 2018, Platanthera guangdongensis and P. zijinensis (Orchidaceae: Orchideae), two new species from China: Evidence from morphological and molecular analyses, Phytotaxa 343 (3), pp. 201-213 : 209

Platanthera zijinensis Q.L. Ye, Z.M. Zhong & M.H. Li sp. nov. (ẾḮǺḆĔ; Figs. 6 , 7 )

Type:— CHINA, Guangdong ( ỮṪ). Zijin ( ẾḮ), in forest edge near the side of the road, alt. 550 m, 31 May 2017, Liu 10275 (holotype: NOCC!).

Diagnosis:— Platanthera zijinensis is similar to P. minor , from which it differs by the ovate-oblong to ovate floral bract (vs. ovate-lanceolate), flower colour (pale yellow sepal, pale yellowish white petal and lip vs. yellowish green), ovate dorsal sepal (vs. broadly ovate), oblong lateral sepal (vs. elliptic), ovate-oblong lip (vs. ligulate), and curved forward spur (vs. pendulous).

Herbs, terrestrial. Plants 35–45 cm tall. Rootstock ellipsoidal, fleshy. Stem erect, stout, 1.0–4.0 × 0.3–1.0 cm, with 1 or 2 tubular sheaths at base, 1-leaved. Leaves cauline, usually widely spaced, elliptic, 5.0–10.5 × 1.1–2.1 cm, base clasping, apex obtuse. Peduncle robust, ridged, with 2–3 foliaceous, lanceolate bracts; rachis 7.0–16.0 cm, laxly 8–17 flowered; floral bracts ovate-oblong to ovate, 0.7–1.9 cm. Flowers opening, sepal pale yellow, petal and lip pale yellowish white; pedicel and ovary 1.1–1.9 cm. Dorsal sepal erect, forming a hood with petals, ovate, 4.0–5.0 × 4.0– 5.0 mm, apex obtuse; lateral sepals revolute, oblong, 5.0–5.5 × 2.0– 2.5 mm, apex obtuse. Petals ovate-elliptic, oblique, 4.0–5.0 × 1.7–2.2 mm, apex obtuse; lip ovate-oblong, 6.0–8.0 × 2.8–3.5 mm, apex obtuse; spur curved forward, cylindric, 1.1–1.5 cm. Column 2–3 mm; staminodes conspicuous; anther locules slightly divergent; connective broad, apex concave; pollinia obovoid, with slender caudicles and suborbicular viscidia; rostellum broad, short; stigma lobes confluent, concave, large, lying directly below rostellum.

Phenology: —Flowering June.

Distribution and habitat: –– Platanthera zijinensis is only known from Zijin country, Guangdong Province, China. It grows in a hillside near the road at 550 m.

Etymology: —The specific epithet refers to the locality of Zijin country where this new species has been found thus far.

Conservation status: ––The new species was found in only one population, which consisted of no more than 50 individuals. Using the World Conservation Union Red List Categories and Criteria ( IUCN, 2016), P. zijinensis should be treated as critically endangered.

Figures

FIGURE 6. Platanthera zijinensis Ye, Zhong & Li.A. Flowering plant. B. Flower, front view. C. Flower, side view. D. Dorsal sepal, petal, lateral sepal, and lip. E. Sheath. F. Pollinarium. Drawn by Li-Jun Chen.

FIGURE 7. Platanthera zijinensis Ye, Zhong & Li. A. Habitat. B. Flowering plant. C. Inflorescence. D. Flower, front view. E. Flower, side view. Photographs by Wen-Hui Rao.