Pollen polyads and their variation inchimaphila(pyrolaceae)

Abstract

The pollen grains of 28 samples representing six species and four subspecies of Chimaphila Pursh were examined by light and scanning electron microscopy. Chimaphila pollen is characterized by polyads composed of an indefinite number of tetrads which is distinct from the pollen in the other genera of the Pyrolaceae, the monads of Orthilia and the tetrads of Pyrola and Moneses. The variation in polyad size among the samples is examined and the confusing terms polyad and massula are clearly redefined. The pollen characters present no distinct differences within the genus, except in C. domingensis Blake, which has a rugulate pollen sculpture. The pollen characters confirm the unity and distinctness of Chimaphila in the Pyrolaceae.