Pachypleurum muliense R. H. Shan & F. T. Pu

This rather poorly known taxon is recorded only from a few collections. Recent research suggests that it is conspecific with Ostericum maximowiczii var. alpinum C. Q. Yuan & R. H. Shan, and should be included in Ostericum at species rank under the name O. muliense.

Plants 70–120 cm. Root cylindrical, ca. 8 mm thick. Stem well developed, single, erect, branching. Basal and lower leaves petiolate, wholly sheathing; blade triangular-ovate, 8–10 × 4–8 cm, ternate-2–3-pinnate, pinnae 4–5 pairs, remote; ultimate segments lanceolate, 5–15 × 1.5–4 mm. Upper leaves reduced, sessile; blade 1–2-pinnate. Umbels 3–7 cm across; bracts 3–5, linear, 0.5–1 cm; rays 5–10, unequal, 1.5–5 cm; bracteoles 3–5, linear-lanceolate, equaling pedicels, scabrous; umbellules 15–20-flowered. Calyx teeth lanceolate, ca. equaling stylopodium. Petals purple, cordate-ovate, base shortly clawed. Stylopodium conic; styles ca. 2 × stylopodium. Fruit oblong-ovoid, 5–6 × 3–4 mm; vittae 2 in each furrow, 4 on commissure. Fl. Jun–Jul, fr. Aug–Sep.

SW Sichuan (Muli).

Low shrubs at streamsides; ca. 2600 m.