HABITAT CORRELATED VARIATION IN FIRECRACKER PENSTEMON (PENSTEMON-EATONII GRAY - SCROPHULARIACEAE) SEED-GERMINATION RESPONSE

Twenty Penstemon eatonii seed collections from a range of habitats were subjected to laboratory chill treatments of 0 to 24 weeks. Germination response during and after chill was correlated with collection site climate. Seeds from sites with colder winters had longer chill requirements and were slower to germinate in continuous chill than seeds from sites with warmer winters. Seeds from variable-winter sites tended to have a large fraction not responsive to chill. Such site-specific responses may function to time germination appropriately and also to provide for between-year seed carry-over in this short-lived perennial species. Field retrieval studies supported these conclusions.