泽库棱子芹 ze ku leng zi qin

Hymenidium tsekuense (R. H. Shan) Pimenov & Kljuykov.

Plants 30–50 cm, glabrous. Root stout, ribbed and branching. Basal and lower petioles 5–8 cm, sheaths ovate; blades broadly triangular, 6–10 × ca. 8 cm, 3–4-ternate-pinnate; petiolules of proximal pinnae 1.5–2 cm; ultimate segments linear-lanceolate, 3–5 × ca. 1 mm. Leaves gradually reduced upwards with short or wholly sheathing petioles. Umbels 4–6 cm across; bracts 3–5, lanceolate, 1.5–2.5 cm, apex pinnate; rays 7–10, 2.5–4 cm, subequal; bracteoles 8–10, narrow-lanceolate, 0.6–1 cm, apex pinnate/pinnatifid; pedicels ca. 5 mm, flattened. Calyx teeth conspicuous, ovate, dark purple, ca. 0.3 mm. Petals broad-ovate or rounded, purplish to white, ca. 1 mm. Anthers black-purple. Stylopodium black-purple, low-conic. Immature fruit ovoid, narrow-winged (mature fruit unknown). Fl. Aug.

Grassy slopes; 3400–3500 m. Qinghai.

This incompletely known taxon is recorded only from a few collections and is part of the Pleurospermum hookeri complex.