Seed Survival and Seasonal Emergence of Seedlings of Some Ruderal Plants

Abstract

(1) Seeds of eleven species which occur as ruderals were collected, usually in each of 3 years, and mixed with the top 7.5 cm of sterilized soil confined in cylinders sunk in the ground outdoors and cultivated three times yearly. Seedling emergence was recorded for 5 years and the numbers of viable seeds remaining then determined. (2) Emergence of Cynoglossum officinale occurred during the first spring. Some seedlings of Plantago lanceolata emerged shortly after sowing, with further seedlings in early spring. Persistence of seeds of both species was of short duration and few seedlings appeared after the second year. (3) The numbers of seedlings of the other species emerging in successive years declined more gradually and the viable seeds remaining after 5 years ranged from 0.6% (Geranium pusillum) to 8.8% (Plantago major) of those sown. (4) There were consistent seasonal patterns of seedlings emergence. Peak emergence of Lamium album occurred from February to April while that of Silene alba, Stachys sylvatica and Urtica dioica was in March or April with further seedlings, especially of S. alba, appearing later in spring and summer. Emergence of Plantago major and Malva neglecta began in April and continued until September, while that of Geranium pusillum and Malva sylvestris was largely restricted to the summer months. Limited data for M. moschata indicated both spring and autumn peaks. (5) It is suggested that information of this kind can be of value in anticipating potential weed problems.