Periodicity of seedling emergence and seed survival in some Umbelliferae.
Abstract
Ten species of Umbelliferae were examined with regard to the time of year at which seedlings emerged and the survival of seeds in cultivated soil. The main time of emergence of Smyrnium olusatrum was in the autumn of sowing while that of Anthriscus sylvestris, Heracleum sphondylium, Angelica sylvestris, Conopodium majus and Pastinaca sativa was in the following spring. Few viable seeds of these species remained after a year. Seeds of Sison amomum, Conium maculatum and Torilis japonica survived for longer. S. amomum had autumn and spring peaks of emergence while C. maculatum and T. japonica were mainly spring-germinating. Maximum emergence of the spring-germinating annual weed Aethusa cynapium occurred in the second or third year and about one-fifth of the seeds were still viable and dormant after 5 years.