CHROMOSOME NUMBERS OF CANADIAN WEEDS. I

摘要

The chromosome numbers of 58 Canadian weeds are reported. Counts obtained on material ofAmbrosia psilostachyaDC. andEpilobium angustifoliumL. differ from those obtained by other workers. The chromosome numbers of the following species had not previously been reported:Silene csereiBaumg. 2nensp;=ensp;24;Axyris amaranthoidesL. 2nensp;=ensp;18;Erigeron philadelphicusL. 2nensp;=ensp;18;Lepidium ramosissimumNels. 2nensp;=ensp;64;Dracocephalum parviflorumNutt. 2nensp;=ensp;14;Rumex fennicusMurb. 2nensp;=ensp;40;R.occidentalisWats. 2nensp;=ensp;ca. 140;R.stenophyllusLedeb. 2nensp;=ensp;60. The significance of some of these chromosome numbers is discussed.