The phenetic relationships of green foxtail [Setaria viridis var. viridis (L.) Beauv.] and its allies were examined by numerical and chemotaxonomic methods. Correlation coefficients and taxonomic distances based on quantitative data from 31 characters displayed close phenetic similarities among green foxtail, its varieties and foxtail millet [S. italica (L.) Beauv.]. Isolation and separation of 35 alcohol-soluble compounds by two dimensional paper chromatography supported the numerical comparisons. By combining all characters examined, the resulting cluster analysis displayed the closest similarity between robust white (S. viridis var. robusta-alba Schreiber), robust purple (S. viridis var. robusta-purpurea Schreiber) and giant green foxtail [S. viridis var. major (Gaudin.) Posp.] indicating that the robust foxtails may be subvarieties of giant green foxtail rather than of green foxtail. The numerical, morphological and chemical comparisons support the proposed phylogeny of the Old World foxtails and indicate green foxtail as the probable center of ancestorial origin.

Aseptic cultures of isolated corn (Zea mays L. ‘North Dakota KE47101′) shoots and roots and soybean [Glycine max (L.) Merr. ‘Hawkeye’] seedlings absorbed and metabolized atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] similarly to plants grown and treated in nutrient solution under non-sterile conditions. Atrazine injured susceptible soybean seedlings more rapidly than can be explained on the basis of starvation alone. It is postulated that the herbicidal activity of atrazine is partly due to toxic secondary factor(s) which may be of biochemical or photochemical origin. The effect of the toxic secondary factor(s) was reversed by added sucrose independent of light.

Leaf surfaces of fifteen plant species contained a large variety of biological and nonbiological structures of various sizes and shapes, which are not a part of the leaf surface but are significant features of all field-grown plants. Some of these structures were fungal hyphae, soil, pollen grains, bacteria, smut teliospores, and many others which could not be identified. This profusion of extraneous material indicates that in-depth studies will have to be made concerning the influence of these materials on agricultural chemicals before the fate of the chemical can be determined with any certainty.