A comparative study of sporophyte morphology of the three cytotypes of Polypodium virginianum in Ontario

Abstract

There are three cytotypes of Polypodium virginianum L. in Ontario. These may be identified by macro- and micro-morphological characters. The most useful characters for identification are frond shape, tip lobing, shape of segment apices, spore size, cell size, and number of paraphyses per sorus. The triploid cytotype, which often overlaps the variation shown by the diploid and tetraploid, can be recognized by a high percentage of aborted spores.