波密无心菜 bo mi wu xin cai

Herbs small, soft. Stems yellow, slender, 5--6 cm, soft, sparsely white pubescent. Petiole 2--6 mm, sparsely villous at base. Leaf blade saccate, 0.5--1.2 cm × 2--3 mm, base attenuate into petiole, margin crisped-undulate, apex acute. Flower solitary, terminal; bracts similar to leaves but smaller. Pedicel slender, 5--9 mm, white villous in 1 line. Sepals 5, ovate, ca. 5 mm, base broadened, margin ciliate at base, apex obtuse. Petals 5, white, obovate, ca. 6 mm, apex emarginate. Stamens 10, shorter than sepals. Ovary ovoid. Styles 3, linear, ca. 4 mm. Fl. Jul.

* Mountain grasslands; ca. 3700 m. E Xizang.

A presumably related species, which has not been validly published ( Arenaria microstella C. Y. Wu in C. L. Tang, Fl. Reipubl. Popularis Sin. 26: 213. 1996), differs from A. bomiensis in having long hairs and small retrorse bristles; leaf blade 2–4 × 1–2 mm, both surfaces raised granular, base attenuate, margin retrorsely ciliate, apex acute; cymes several flowered; and styles 3. It is known from shifting screes, from 4200 to 4300 m, in SW Sichuan.