Spore Morphology and Cytology of Isoetes Azorica (Pteridophyta Isoetaceae) and ITS Affinity with North America

Isoetes azorica is an endemic of shallow, oligotrophic lakes in the Azores Islands. Cytological investigations determine it to be tetraploid (2n=44). Morphological studies indicate that it shares many characteristics with the North American tetraploid I, tuckermanii. The spore morphology of both species is illustrated by SEM and their degree of similarity discussed. The apparently close affinity between these two taxa is consistent with phytogeographic patterns noted with few other pteridophytes of this region.