Temporal growth patterns and adaptive characters were studied in 17 perennial, 16 annual, and 4 biennial native herbs for one to three growing seasons in dry—mesic, mesic, and wet—mesic forest and in open barrens in southern Wisconsin. In annuals almost all dry matter produced was retained in aerial organs following the initial growth period. Below—ground weight increased rapidly in early season and then slowly increased or declined. In perennials there was a predominantly upward weight movement during growth initiation and during flowering and fruiting and a downward movement between growth initiation and flowering and preceding aboveground senescence or death. Between autumn and spring, all perennials, including wintergreens, lost weight. Most winter annuals increased in both above— and below—ground dry weight over winter, demonstrating maintenance above the compensation point. Growth patterns of biennials in their first year were similar to perennials and in their second year were similar to annuals. Forest herbs lost less water before wilting, were more succulent, wilted in a shorter time, and had heavier seeds than herbs of open habitats. The seeds of the forest annuals were heavier and germinated more readily than seeds of forest perennials. Although most annuals are pioneer, drought—resistant plants, fores annuals wilted easily and were very succulent. This suggests that stems and leaves of the annuals apparently are supported more by turgor pressure, while the perennial plants are supported more by cell wall thickening. This special dependence of annuals on water correlates with their greater numbers in wet—mesic and mesic forests compared with drier forests. Growth characteristics are discussed for eight forest annuals: Amphicarpa bracteata, Ellisia nyctelea, Floerkea proserpinacoides, Galium aparine, Impatiens pallida, Parietaria pennsylvanica, and Pilea pumila.

Response of seeds of Pinus taeda and P. strobus to light. Plant Physiol. 37: 228-233. Wareing, P. F., and M. Black. 1958. Photoperiodism in seeds and seedlings of woody species, p. 643-654.In K. V. Thimann, [ed.], The physiology of trees, Ronald Press, New York.Abstract. A connection is suggested between two well-known but hitherto unrelated phenomena : germination under field conditions of certain seeds following soil disturbance and germination in laboratory experiments of certain seeds following brief exposures to light. A light-flash mechanism for breaking dormancy is proposed as a possible adaptation aiding pioneer plants in exploitation of disturbed habitats.

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Seven forest herbs had a higher below—ground dry matter production in a dry forest than in a mesic or moist forest. Zea mays had a higher relative below—ground production in a droughty portion of a field than in a non—droughty.Root/shoot ratios tend to increase with increasing xericness of the habitat.

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