Ecological life cycle of Chaerophyllum procumbens variety shortii (Apiaceae), a winter annual of the North American Eastern Deciduous Forest

Seed dormancy and germination, flowering, and biomass allocation patterns of the deciduous forest species Chaerophyllum procumbens var. shortii were investigated relative to its winter annual life cycle. It was determined that seeds had nondeep simple morphophysiological dormancy at maturity in late May. The physiological component of dormancy was broken during summer, and embryos grew (morphological component) in autumn if seeds were exposed to light. Seeds sown in late spring germinated only in autumn, but a few did not germinate until the second to seventh autumn, indicting the potential to form a small persistent seed bank. Vernalization was not required for flowering. In the field, plant growth and development occurred during autumn, winter, and early spring, and individual plants reached highest total plant biomass [0.28 ± 0.01 g (mean ± SE)] at flowering. Total plant biomass decreased from flowering to mericarp maturity. In two successive years, the proportion of total biomass allocated to roots (≤ 22.2 ± 2.9%) at five growth stages was less than that allocated to any other vegetative structure. Changes in biomass allocation during reproductive growth stages occurred only in above-ground structures. Although mass of reproductive structures was strongly correlated with plant vegetative mass, differences in slopes of the regressions between years indicated that between cohort differences in percent reproductive allocation were not completely accounted for by overall plant size.