Structure, Distribution and Taxonomic Significance of Trichomes In Some Cucurbitaceae

The present LM and SEM investigations deal with the structure, distribution and taxonomic importance of trichomes in 16 genera and 31 species of Cucurbitaceae. Of these, 13 genera and 23 species have been studied for the first time. Presently, nine trichomes types are recorded viz., unicellular conical, uniseriate filiform capitate, uniseriate filiform clavate, uniseriate filiform cylindric-clavate, uniseriate filiform branched, uniseriate macroform conical, uniseriate macroform curved, uniseriate macroform cylindrical and uniseriate macroform candelabra hair types. Of these, uniseriate filiform capitate and uniseriate macroform conical trichome types are present on both the vegetative and floral parts. These types are considered as trichome markers of the Cucurbits studied. Uniseriate filiform cylindric clavate hair is common to all tribes of the Cucurbitaceae excepting Joliffieae and Sicyeae. The genus Cucurbita is unique by the exclusive presence of uniseriate macroform candelabra hair and it is totally absent in the rest of other Cucurbits studied.