Germination of Silene regia Seeds from Four Sites in Lawrence County, Illinois, Following Scarification or Stratification

Silene regia Sims is an endangered prairie forb in Illinois where small isolated colonies are scattered. In La·wrence County, two sites (Allison Prairie and Chauncey Marsh) have fewer plants (6-23) than two other sites (Cmmty Road and Cemetery) with 26-45 plants. Information on seed germination in these isolated colonies is needed. Our goal was to evaluate seed germination of S. regia from colonies in Lawrence County, illinois. S. regia fruits were collected from these four sites on August 9 and 19, 1999. Seeds were scarified by cutting the seed coat, or they were stratified at 2 C for 12 or 15 weeks. Seeds from Chaun.cey Marsh weighed less than those from other sites. With the exception of seeds from Chauncey Marsh, scariiication increased gemrination within each site. When significant germination differences occurred due to site, they were apparent on stratified seed, where frequently Allison Prairie was highest and Chauncey Marsh was lowest. Germination clifferences between stratified and control seeds were inconsistent, although stratified seeds had up to 67% higher gemrination than control seeds when significant differences occurred. These increases in seed germination were most evident in seeds collected on August 9th and stratified for 12 weeks. Seed that was neither scarified nor stratified gemrinated after storage, indicating that scarification and stratification are not absolute gemrination requirements with after-ripened seeds. Seed germination at different sites did not correspond directly with population sizes, and multiple mechanisms were present for breaking seed donnancy in S. regia