Chromosome counts have; been obtained for 71 collections; seven tribes, 11 genera, and 39 species of the Leguminosae are represented. Pollen mother cells were collected in the field and examined in acetocarmine. Twenty of the species studied were in the tribe Galegeae: Astragalus 14 species, Oxytropis five species, and Glycyrrhiza one species. Twenty-nine of the counts have not been published before. Consideration is given to the phylogeny of Astragalus. Evidence suggests that Astragalus should be subdivided.

No abstract

No abstract

Avena fatua L. (wild oats), an introduced annual, is a successful weed in the cultivated fields of the Canadian prairies. Its inflorescence is a determinate panicle consisting of many spikelets, each of which contains two or three florets. During anthesis, the lodicules in each floret swell after water uptake and cause the lemma to diverge and to establish a wide angle between it and the palea. The essential organs in the floret are exposed to the environment and subsequently the anthers dehisce releasing pollen. The pollen grains are dropped on the stigmatic branches, thus effecting self-pollination. Following pollination, the floret closes because of the collapsing of lodicules. The pollen on the stigma germinates after the floret has closed. Anthesis, both in the field and in the growth cabinet, shows a daily rhythm and occurs in the afternoon. This rhythmic floret opening seems to be temperature sensitive. The ambient temperature range for anthesis in the field is 25–28 °C. The wild oat is primarily a chasmogamous species and enforced cleistogamy in the florets can be induced experimentally.

No abstract