Description from Flora of China
Mesostemma martjanovii (Krylov) Ikonnikov.
Herbs perennial, glandular hairy. Stems 3--6 cm tall, simple or sparsely branched. Leaves congested, sessile, oblong-ovate, 5--7 × ca. 3 mm, midvein conspicuous, apex acuminate. Flowers axillary or terminal. Pedicel 5--7 mm or longer, pendulous at anthesis. Sepals 4, ovate-lanceolate, ca. 4 × 2 mm, margin narrowly membranous, apex acute. Petals 4, ca. 1.5 × as long as sepals, ca. 6 × 4 mm, 2-cleft to 2/3 length; lobes oblong-obovate. Stamens 8. Capsule ovoid, 4-valved to base, slightly longer than persistent sepals. Fl. Apr--Jul.
Stellaria alexeenkoana Schischkin (in Komorov, Fl. URSS 6: 882. 1936; Mesostemma alexeenkoana (Schischkin) Ikonnikov) was described based on a specimen from Tagdumbasch Pamir (Xinjiang). It is similar to S. martjanovii, but has linear-oblong leaves, pubescent sepals, and petals shorter than the sepals. The present authors have seen no material of this taxon.
Stony slopes; Xinjiang (Altay Mts.) [Russia].