Germination ecology of Collinsia verna, a winter annual of rich deciduous woodlands.

Seeds are innately dormant at dispersal in late May and early June, but during summer they afterripen and become nondormant. During the afterripening period, seeds gained the ability to germinate in light and darkness at 15/6, 20/10, 25/15 and 30/15oC. Seeds 1st germinated at 15/6oC (in July) and then at progressively higher temperatures. Germination at 30/15oC was delayed until October, at which time <25% of seeds germinated. After germination began at a particular temperature regime, the germination percentage at that temperature increased as the seeds afterripened further, and by October seeds germinated from 82-88% in light and darkness at 15/6 and 20/10oC. From July through September habitat temperatures are too high for germination; seeds do not germinate until early autumn when temperatures become non-limiting.-from Authors