From 1935 to 1939 inclusive, laboratory and field studies were made of the production, viability, impermeability, longevity and germination of seeds of Convolvulus arvensis L. and of other deep-rooted perennial weeds. A summary of the results is as follows:

Bindweed plants, Convolvulus arvensis, produced an abundance of seed in seasons of high temperature and low rainfall. Periods of cloudy weather restricted blossoming and seed production.

Production of normal seedlings by seeds, immediately after collection on the plants, varied from 7 to 24 percent, impermeability in the same collections varied from 28 to 91 percent and dead seeds ranged from 2 to 51 percent. The range in percentage of dead seeds in lots from 1 to 72 years old was 2 to 100.