TAXONOMIC VALUES OF TRICHOMES TYPES IN MALVACEAE SUBFAMILY BOMBACOIDEAE AND HELICTEROIDEAE
A study was conducted on 24 selected species of Bombax, Coelostegia, Durio, Kostermansia, Ochroma and Pachira from the Malvaceae subfamily Bombacoideae and Helicteroideae. Objective of this study was to identify leaf micromorphological characteristics which can be used as secondary data for scientific research especially in species, genus and family classification. Observation was conducted under electron scanning microscope on adaxial and abaxial epidermal surface of gold coated dried leaves with various magnification. Results showed there was some significant variation in the types of trichomes of all species studied. These trichome characteristics have taxonomic value and can be used for classifications up to species and genus level. Lepidote trichome was seen as a common character in Coelostegia, Durio, Kostermansia, Ochroma and Pachira but not in Bombax. Capitate glandular trichomes with multiseriate terminal (spathulate terminal lobes) could only be found on adaxial epidermal of B. anceps and dendritic trichomes could only be found in D. affinis. Trichome diversity in Pachira was even more unique as seen in three-armed trichomes (swollen in the middle arm) and non-cushioned stellate trichomes (short armed, thin wall, swollen in the middle and at the end). In conclusion, trichomes have taxonomic value in Malvaceae subfamily Bombacoideae and Helicteroideae.