STRATIFICATION IMPROVES SEED-GERMINATION OF 5 NATIVE WILDFLOWER SPECIES

The germination responses of wild blue indigo [Baptisia australis (L.) R. Br.], purple coneflower [Echinacea purpurea (L.) Moench.], Maximil ian sunflower (Helianthus maximiliani Schrad.), spike goldenrod (Solid ago petiolaris Ait.), and Missouri ironweed (Vernonia missurica Raf.) seeds after 0, 2, 4, 6, 8, or 10 weeks of stratirication at 5C were in vestigated. Seed viability was determined using triphenyl tetrazolium chloride staining and germination based on the percentage of viable se eds. Germination percentage (GP) increased in all five species as week s of stratification increased. Days to first germination and germinati on range (days from first to last germinating seed) decreased with inc reasing weeks of stratification, but the effect beyond 4 to 6 weeks wa s minimal. The number of weeks of stratification for maximum GP was 4 for purple coneflower, 6 for Maximilian sunflower, 8 for Missouri iron weed, and 10 for wild blue indigo and spike goldenrod.