CYTOTAXONOMY OF EUPHORBIA ESULA IN CANADA AND ITS HYBRID WITH EUPHORBIA CYPARISSIAS

摘要

In 14 collections of leafy spurge from Ontario and Saskatchewan the chromosome number is 2nensp;=ensp;60. The problem of the correct botanical name of this plant is reviewed; all the North American collections seen are classed asE.esulaL. sensu lato. The morphology and cytology of an artificial hybrid,E.cyparissiastimes;E.esula, is described; its chromosome number is 2nensp;=ensp;50 and meiosis is irregular. The nameE. times;figertiiDouml;rfler usually applied to this hybrid is rejected in favor of the prior nameE. times;pseudo-esulaSchur.