Germination Ecology ofLiatris ohlingerae(S.F. Blake) B.L. Rob. (Asteraceae), an Endangered Herb Endemic to Florida Scrub

Abstract

Seed source, absence of favorable microhabitat conditions, and presence of competitors, predators or allelochemicals are among the many factors that may limit the germination of viable seeds. We conducted six field, growth chamber, and veranda experiments to investigate the effects of seed source, physical or chemical presence of co-occurring species, and litter presence on germination percentages of the Florida scrub endemic Liatris ohlingerae. This perennial herb produces many seeds but recruits few seedlings. Germination percentages were similar when seeds from scrub and roadside habitats were sown into their own and the contrasting habitat. We found no evidence of chemical inhibition from a co-occurring terrestrial lichen or from the allelopathic Florida rosemary (Ceratiola ericoides), the dominant shrub in the habitat preferred by L. ohlingerae. However, germination was higher in shallow than in deep litter, and was suppressed by litter from oaks and pines compared to litter from Florida rosemary. In one experiment, higher levels of post-sowing seed predation closer to Florida rosemary shrubs limited germination. Germination of intact L. ohlingerae seeds generally exceeded 60% under a range of field and lab conditions. High field germination percentages within a few weeks of sowing suggest that L. ohlingerae does not maintain a sizeable persistent seed bank. Low seedling recruitment in this endangered plant is not likely caused by poor seed germination.