Cytotaxonomical study of the species and natural hybrids of genus Drosera (Droseraceae) in Quebec

A cytological study of 25 individuals from different Drosera populations sh ows that the chromosome number of the four taxa occurring in Quebec confirm s the results already published for these species and does not vary. Droser a rotundifolia L., D. intermedia Hayne and D. linearis Goldie possess 2n = 20 chromosomes, while D. anglica Huds, has 2n = 40. Three different hybrids however were detected: D. rotundifolia x D. linearis (2n = 20), D. lineari s x D,. anglica (2n = 30) and D. rotundifolia x D. anglica (2n = 30). The o ccurrence of the latter hybrid, well known in Europe and Japan (D. x obovat a Mert. & Koch), is cytologically confirmed for the first time in eastern N orth America. The name D, x linglica Kusakabe ex Gauthier & Gervais is sugg ested for the linearis-anglica hybrid. while D. x woodii Gauthier & Gervais is proposed for the linearis-rotundifolia progeny. The existence of sponta neous crosses involving D. rotundifolia, D. anglica and D. linearis is cons istent with the hypothesis that D. anglica is an amphiploid resulting from the chromosome doubling of the sterile linearis x rotundifolia hybrid. The meiotic pairing configurations observed in a linearis x anglica (2n = 30) h ybrid suggest however that the process must have taken place with a primiti ve D. linearis somewhat different from the present species. D, linearis is a species with narrow ecological requirements whose northeastern American l ineage with some isolated western populations alone subsist and need protec tion.