| Abstract: | Morphological and cytological analyses of several specimens of the genus Nitella suggest that species described as N. stellaris, N. lindheimeri, N. gollmeriana, and N. mexicana and some forms reported as N. acuminata var. subglomerata represent a single taxon in the N. acuminata species group. Cytological examination revealed a chromosome number of n = 9 in the specimens from the study area but N. acuminata is known to display n = 18 chromosomes in other regions of North America and on oilier continents. Hypotheses regarding the origin and significance of this polyploidy are discussed. The habitats supporting N. acuminata (n = 9) in the study area show some features which are in contrast to those of habitats supporting the species (n = 18) in other areas of North America. |
