I.M. Johnst.
Description
Trigonotis tibetica is a small alpine forget-me-not relative distributed across the Tibetan Plateau and the high Himalaya, recorded from China, India, Nepal, Bhutan and Pakistan, and reasonably well collected (c. 278 records in GBIF) across this broad arc. It inhabits open alpine turf, gravelly slopes, stabilised screes and the margins of meadows, typically between about 3500 and 5000 m, where snowmelt provides moisture through the brief summer. The photographed plant from West Nepal at Baga-La-Phedi (4300 m, July) is typical of the species in mid-summer flower in this cold, well-drained high-elevation setting.
The plant is a low, often tufted perennial herb with a slender taproot and prostrate to ascending stems, the whole frequently appressed-strigose or hispid. The leaves are small, spathulate to oblong-elliptic, entire, and crowded toward the base. The inflorescence is a short, ebracteate or basally bracteate cyme that elongates in fruit; the flowers are small and gamopetalous, with a blue (occasionally white) rotate to shallowly campanulate corolla bearing five vaulted faucal scales at the throat. The androecium has five included stamens; the gynoecium develops into the characteristic four nutlets, which in Trigonotis are conspicuously trigonous and tetrahedral, often borne on short gynobasic stalks.
The genus Trigonotis (tribe Trigonotideae) is distinguished from Myosotis and allied forget-me-nots chiefly by these sharply angled, pyramidal nutlets. Note that this taxon has historically been treated under Microula, and the source links accordingly to a Microula tibetica page; current nomenclature places the accepted name in Trigonotis. As a widespread plateau and Himalayan alpine, the species is not considered threatened.
Author: I.M. Johnst. · Sources: POWO (Kew), GBIF, Flora of China (Boraginaceae), Flora of Nepal, Flora of Pakistan, Monograph of Trigonotis (I.M. Johnston)