THE EFFECTS OF SEED MASS ON THE SEED ECOLOGY OF COREOPSIS-LANCEOLATA

We examined the effects of seed mass on seed survival and germination in the herbaceous perennial Coreopsis lanceolata (L.) (Asteraceae). Seeds were collected from bagged flower heads, weighed and sorted into mass classes. Seed mass variation was 29-fold (range 0.111 to 3.210 mg), almost twice as high as in other species. For seeds buried in soil flats 0, 1, 2, 3 and 4 cin, larger seeds had greater viability, emerged from lower depths, and had higher emergence rates. After 2-yr burial in nylon bags in the field, larger seeds had higher survivorship and viability rates but lower germination rates. The lower germination rates of large seeds after burial in the field may be due to dormancy. This study is the first to test seeds previously buried and recovered for survival, viability and germination. Seed-mass variation may be maintained by differential dormancy and germination which results in spreading the risk of recruitment.