Some taxonomic implications of pollen and seed morphology in Mimulus hymenophyllus and M. jungermannioides and comparisons with other putative members of the M. moschatus alliance (Scrophulariaceae)

Abstract

Statistically significant differences in pollen and seed size confirm the distinctness of Mimulus hymenophyllus and M. jungermannioides and distinguish M. hymenophyllus from all other members of the M. moschatus alliance. Published descriptions of morphological differences in the seeds of M. jungermannioides, M. patulus, and M. washingtonensis are not confirmed. The pollen evidence is consistent with a segregation of M. moniliformis from M. moschatus but fails to support a previously reported difference in exine sculpturing between M. moschatus and M. inodorus. Other taxonomic implications of the pollen data are discussed. Expanded study on aperture morphology in Mimulus pollen has revealed that some species of the M. moschatus alliance and other species of section Paradanthus have predominantly unruptured colpus membranes, and the description of the pollen of this section is emended to include this aperture type.