Distribution patterns of glandular trichomes in the flora of the Hengduan Mountains, southwestern China.

This article focuses on the occurrence and evolutionary patterns of glandular trichomes—specialized plant structures involved in chemical defense—across 7,751 angiosperm species in the Hengduan Mountains region of southwestern China. The study found that 13.2% of species possessed glandular trichomes, with a significantly higher presence on reproductive organs (88.0%) than vegetative organs (59.1%), and a greater prevalence in herbaceous (14.0%) compared to woody species (11.6%). Leaf habit influenced glandular trichome occurrence on reproductive organs but not on leaves, while tropical geographic elements showed a lower proportion of species with glandular trichomes than temperate or cosmopolitan elements. Phylogenetic relatedness had a limited effect, suggesting that environmental factors and organ-specific fitness value primarily shape the evolution and distribution of glandular trichomes in this diverse flora.