On the pollen morphology of Picea and Tsuga species

Abstract

Pollen grains of Picea orientalis, P. sitchensis, Tsuga heterophylla, and T. mertensiana were investigated by means of light, scanning electron, and transmission electron microscopy. The fine structure of these four species, the siamcsc pollen in P. sitchensis, and the variations in sacci of T. mertensiana were demonstrated. Pollen morphology of T. mertensiana differed from that of Picea, and even more from T. heterophylla. The difference in morphology of Tsuga species may have been due to varying rates of evolutionary change, to the modification of reproductive structure for their continued existence, or to introgrcssion. From the differences in pollen morphology, the authors consider that the two Tsuga spccies could be assigned to separate genera. © 1972 Taylor & Francis Group, LLC.