An SEM Survey of the Leaf Epidermis in Danthonioid Grasses (Poaceae: Danthonioideae)

Abstract

This study comprised a scanning electron microscope survey of abaxial epidermal features in subfamily Danthonioideae, with emphasis on North American Danthonia. The survey included 21 taxa, encompassing seven genera (Austrodanthonia, Cortaderia, Danthonia, Merxmuellera, Notodanthonia, Rytidosperma, Tribolium) and the eight North American Danthonia species. We investigated micromorphological characters to determine taxonomic utility and whether North American representatives of Danthonia are distinct. We examined micromorphological epidermal features: macrohairs, bicellular microhairs, prickle hairs, silica bodies, and stomata. We found no distinguishing characters at the subfamilial level. Danthonia is characterized by the absence of abaxial stomata and presence of bicellular microhairs with basal and terminal cells of equal length and microhairs with long basal cells relative to terminal cells. Prickle hairs in the abaxial epidermal costal regions of four species of North American Danthonia are reported for the first time.