Sex-specific germination response in the liverwort Sphaerocarpos texanus (Sphaerocarpaceae)

The sexually dimorphic liverwort, Sphaerocarpos texanus, can be used to study changes in sex ratios in a cohort of individuals during different life stages, from spore development to germination to senescence. Recent attempts to germinate spores under controlled conditions have been successful. This study used laboratory-derived spores to detect subtle sex-specific differences in germination in a cohort of spores across different dormancy breaking temperatures. Sex ratios were determined for subsets of sporelings hem at 35/20, 30/15, and 25/15°C for one to eight wk. Sex ratios were female biased for spores that lost dormancy in the 25/15°C and when the data were pooled across the three dormancy breaking thermoperiods. This pattern coupled with the potential for spore banks formation in S. texanus can lead to a single cohort of spores influencing the sporeling sex ratios across seasons.