Platanthera xizangensis X.H.Jin, S.Yan, T.Pandey

Platanthera xizangensis X.H.Jin, S.Yan, T.Pandey ( Figure 2 View FIGURE 2 , 3 View FIGURE 3 , 4 View FIGURE 4 ), sp. nov.

Type:— CHINA. Xizang Autonomous Region, Nyingchi City, Motuo County, 3,790 m, 31 Aug 2024, Xiaohua Jin et al. 60077 (holotype: PE!, isotypes: PE!).

Diagnosis: Platanthera xizangensis is morphologically close to P. milinensis by sharing partially open, spurless, greenish flowers, however, differs from it in having lip with lateral lobes basal, lip apex fleshy, and obtuse, subsecund lax inflorescence, and two subopposite, lanceolate leaves.

Description: Terrestrial herbs, 7–12 cm tall. Rootstocks oblong-fusiform, stoloniferous, ca. 1 cm long, new shoot arising from the apex of new tuberoid, densely covered with root hairs throughout their length. Stem erect, with one or two basal sheaths. Leaves two, subopposite; blades lanceolate, midvein depressed, 1.5–2.0 cm long, 0.5–0.75 cm wide, margin entire or slightly wavy, apex acute to subacute. Inflorescence subsecund raceme, with one or two foliaceous sterile bract, lanceolate, apex subacute; rachis 3–5 cm long, subdensely 8–10-flowered; floral bracts lanceolate with sub-obtuse apex. Flowers yellowish-green, partially opened, resupinate, 4–5 mm across; ovary obovate-elliptic with curved tip, 3–4 mm long. Sepals and petals connivant forming a hood; sepals sub-equal, externally glandular, ca. 3 mm long, ca. 1 mm broad, concave, apex obtuse; dorsal sepal ovate-elliptic, dorsally with a median ridge; lateral sepals oblique, oblong-elliptic with tapering apex, margins often crenulate; petals smaller than sepals, whitish green, ovate-elliptic, ca. 2 mm long, ca. 1 mm broad. Lip triangular ovate, base concave with 3 conspicuous calli, 3-lobed, lateral lobes basal, erect, ca. 0.5 mm long, margin incurved with rounded apex, mid lobe ligulate, ca. 3 mm long, apex fleshy, obtuse, spur absent. Column erect, 1–1.5 mm long, anther locules parallel, pollinarium ovate, ca. 0.5 mm long; auricles prominent, whitish; rostellum slightly triangular, stigma transverse, lateral lobes not protruding and indistinct.

Etymology: The epithet refers to Xizang Autonomous Region ( China), the location where types were collected.

Distribution and habitat: Platanthera xizangensis was found in the humid alpine meadows, at elevation of ca. 3,790 m.

Phenology: Flowering in July–September.