CHROMOSOME NUMBERS IN SOME MOSSES FROM QUEBEC

Abstract

The results of chromosome studies of five species of mosses from the Mont Tremblant area of Quebec are presented. The chromosome numbers of two species, Plagiothecium roeseanum (Hampe) B.S.G., with the number n = 20, and Polytrichum ohioense Ren. & Card., with the number n = 14, are reported for the first time. Both species are established tetraploids with no evidence of chromosome irregularities in meiosis. Chromosome numbers reported for the other three species are as follows: Dicranum rugosum (Hoffm.) Brid., n = 12; Dicranum scoparium Hedw., n = 12; and Plagiothecium denticulatum Hedw., n = 20. The population of D. rugosum that was studied did not possess small precociously separating bivalents as have been reported for European populations. The close resemblance of the chromosome complements of P. denticulatum and P. roeseanum is in line with the close taxonomic relationship between the two species. Cytotaxonomic implications are discussed under each species.