Pollia is a genus of flowering plants in the family Commelinaceae (order Commelinales), comprising around 20 species of tropical and subtropical herbs. The genus was first described in 1781 and belongs to the dayflower family, a group known for its often ephemeral, three-petalled flowers and jointed, fleshy stems.
Members of Pollia are typically rhizomatous perennial herbs found in shaded forest understories, stream margins, and moist woodland habitats across the Old World Tropics. The genus is distributed through tropical and subtropical Africa, southern Asia (including the Himalayas, South and Southeast Asia), China, Japan, Korea, Taiwan, and northern Australia. One species, Pollia americana, occurs in Panama, representing the genus's sole presence in the New World.
The genus is notable for Pollia condensata, a tropical African species that produces some of the most structurally coloured fruit known in the plant kingdom. Unlike most plant pigments, the iridescent blue colour of Pollia condensata berries is produced entirely by structural coloration — thin-film interference in the cellulose layers of the fruit wall — rather than chemical pigments, making the colour extremely persistent even in dried or preserved specimens.
Distribution
Pollia is distributed widely across the Old World Tropics, with species occurring in tropical and subtropical Africa, southern Asia (including the Indian Subcontinent and Himalayas), Southeast Asia, China, Japan, Korea, Taiwan, northern Australia (Queensland, New South Wales), Madagascar, New Guinea, and the Pacific Islands. A single species, Pollia americana, is endemic to Panama and represents the only New World occurrence of the genus.
Taxonomy Notes
Pollia was first described as a genus in 1781. It is placed in the family Commelinaceae, order Commelinales, class Magnoliopsida. GBIF recognises 11 accepted species. The genus includes naturally occurring hybrids, such as Pollia × horsfieldii (P. secundiflora × P. thyrsiflora) and Pollia × zollingeri (P. hasskarlii × P. secundiflora), both from Java.
