Corispermum hyssopifolium on the Lake Michigan Dunes Its Community and Physiological Ecology

1. Corispermum hyssopifolium L., a summer-annual member of the Chenopodiaceae, has a wide geographic range but is ecologically restricted. 2. In the Lake Michigan area it occurs primarily on five major phytophysiographic sites: eroding surfaces; depositing surfaces; stable surfaces, Ammophila breviligulata dominant; stable surfaces, Ammophila-Andropogon scoparius transition; and stable surfaces, Andropogon dominant. It is apparently not found on neighboring non-dune sites. 3. Considerable variation in density of bugseed was found among these sites, and individuals growing on them also showed considerable variation in vigor. 4. Largest individuals in the dunes were found to be associated with buried organic matter, presumably because of better nutrient supply. 5. Bugseed plants were found experimentally to grow very vigorously when supplied with a high level of nutrients in a "complete" solution applied in white quartz-sand culture. They are able to grow and survive as very small unbranched plants for over...