Edgew.
Description
Commelina maculata is a perennial herb of the Himalaya and adjacent Asian mountains, recorded by GBIF from China, Nepal, India, Thailand, Bhutan, Myanmar, Vietnam and Sri Lanka across about 310 occurrences. It grows in moist, often shaded places, along forest margins, on grassy and rocky banks, beside paths and watercourses, and in disturbed ground, generally at low to middle elevations. The plant photographed at Punakha in western Bhutan at about 1310 m, flowering in May, occupies the warm temperate valley habitat where this species is common in the early monsoon season.
The plant has ascending to decumbent, somewhat fleshy stems that root at the lower nodes, with sheathing leaf bases typical of the family. The leaves are alternate, lanceolate to ovate-lanceolate, with entire margins and a closed basal sheath, often with a fringe of hairs at the sheath mouth. The flowers emerge from a folded, boat-shaped spathe and are zygomorphic, with three sepals and three petals of which the two upper petals are larger and conspicuously blue, the lower one reduced and paler; there are six stamens, several modified as staminodes with cruciform antherodes. Each flower is ephemeral, opening for part of a single day. The fruit is a small loculicidal capsule containing few rugose seeds.
Commelina is a large pantropical genus whose Asian montane species, including C. maculata, are distinguished by spathe form, seed sculpturing and indumentum. The fleeting, nectarless flowers rely on pollen-foraging insects, and the staminodes function as a visual lure. As a plant of disturbed and marginal habitats the species is weedy, resilient and widely distributed, and it is of no conservation concern. Its broad Indo-Malayan to Himalayan range reflects the success of the genus in seasonally moist, sunny situations.
Author: Edgew. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Faden Commelinaceae studies, Annotated Checklist of the Flowering Plants of Nepal