Effects of temperature, seed provenance, and substrate on germination of the endemic and threatened Paper nailwort (Paronychia chartacea ssp. chartacea).

Paper nailwort (Paronychia chartacea ssp. chartacea) is an endemic and threatened herb restricted to central Florida. There is limited information on seed propagation for this species. We tested the effects of temperature [22/11 °C (winter), 27/15 °C (spring), 29/19 8C (fall), and 33/24 °C (summer)], substrate (filter paper vs native soil), provenance (two collection locations), and time in dry storage on seed germination in three experiments. Germination was generally higher in cooler temperatures (~50-70%; winter or spring) compared to warmer temperatures (~0-25%; fall and summer), with overall germination highest at the spring temperature. We also found that germination increased up to 94% for seeds at fall and summer temperatures when they were transferred to winter temperatures at 32 days (i.e., warm stratification improved germination), and increased from 1% to 24% when seeds were sown at 15/5 °C and transferred to 27/15 °C. No significant differences were found between substrate or provenance. Overall germination rates increased over time in dry storage. These data indicate seeds of paper nailwort are non-dormant, non-deep physiologically dormant, or a combination of the two, prefer cooler to warmer temperatures for germination overall, prefer a warm pretreatment, and can be dry stored for at least four months. [ABSTRACT FROM AUTHOR]