Saxifraga sessiliflora H. Sm.

Herbs perennial, 2-3 cm tall. Shoots numerous, with leaf rosettes. Rosette leaves imbricate, narrowly obovate-spatulate, abaxially convex, adaxially concave, 4-6 × 1.4-2.5 mm, both surfaces glabrous, margin setose-ciliate, apex obtuse, aristate. Flower solitary, sessile or subsessile; pedicel 0-1 mm, glandular hairy. Sepals erect, ovate, 3-4 × 2-3 mm, both surfaces glabrous, veins 3, not confluent at apex, margin setose-ciliate, apex obtuse. Petals white, pink at base, broadly elliptic to broadly ovate, 5-9 × 3-5 mm, not callose, 5-veined, base gradually narrowed into a claw 1-2.5 mm, apex rounded or retuse. Stamens ca. 3 mm. Ovary subsuperior, ovoid, ca. 2.5 mm; styles ca. 2.2 mm. Fl. Jul-Aug.

Herbs perennial, 2-4 cm tall. Shoots numerous, with leaf rosettes. Stem slender, glandular hairy. Rosette leaves imbricate, narrowly obovate-spatulate, abaxially convex, adaxially concave, 3-4 × 1-1.5 mm, both surfaces glabrous, margin setose-ciliate, apex acute, aristate. Cauline leaves 3 or 4, obovate, oblong, or linear, 3-4 × 1-1.5 mm, both surfaces glabrous, margin setose-ciliate, apex acute, aristate. Flower solitary; bracts similar to cauline leaves, ca. 3.4 × 1.8 mm; pedicel 0.5-1.5 cm, densely glandular hairy. Sepals erect, ovate to oblong, 3-3.5 × 1.5-2.5 mm, both surfaces glabrous, veins 3, not confluent at apex, margin setose-ciliate, apex obtuse. Petals white, pink at base, obovate to narrowly so, 5-8 × 2.5-4 mm, not callose, 3-5-veined, base gradually narrowed into a claw 1-1.2 mm, apex rounded or retuse. Stamens ca. 3 mm. Ovary subsuperior, ovoid, ca. 2.5 mm; styles ca. 2.2 mm. Fl. Jul-Aug.

S Xizang (Gyaca Xian, Lhasa Shi, Lhünzê Xian).

SE Xizang.

* Alpine scrub, meadows, rock crevices; 4200-5000 m.

* Rocky hillsides; 4400-4700 m.

Saxifraga gyacaensis J. T. Pan.

Flowering from July to August.

Saxifraga sessiliflora is occurring in S Xizang of China.

Phylogenetic analysis of the largest section of the genus Saxifraga (Saxifragaceae), sect. Ciliatae was inferred from the ITS sequences of the nuclear ribosomal DNA (Zhang et al., 2008). Results indicated sect. Ciliatae, as traditionally defined, constitutes as a monophyletic clade. Saxifraga sessiliflora belongs to this section.

Herbs perennial, 2-3 cm tall. Shoots numerous, with leaf rosettes. Rosette leaves imbricate, narrowly obovate-spatulate, abaxially convex, adaxially concave, both surfaces glabrous, margin setose-ciliate, apex obtuse, aristate. Flower solitary, sessile or subsessile; pedicel subsessile, glandular hairy. Sepals erect, ovate, both surfaces glabrous, veins 3, not confluent at apex, margin setose-ciliate, apex obtuse. Petals white, pink at base, broadly elliptic to broadly ovate, not callose, 5-veined, base gradually narrowed into a claw 1-2.5 mm, apex rounded or retuse. Stamens ca. 3.5 mm. Ovary subsuperior, ovoid, ca. 2.5 mm; styles ca. 2.5 mm.

Growing in alpine scrub, meadows, rock crevices; 4200-4900 m.