Seed Germination of Three North American Pinguicula Species

Over 100 species of Pinguicula can be found worldwide. In North America, Pinguicula species can be found primarily in the southeastern USA (6 of 9 species). Of these southeastern species, 83% are state listed as threatened or endangered in Florida, and one species, P. ionantha, is also federally listed as threatened. In recent years, new information has emerged regarding the reproductive ecology, prey capture, population genetics, and impact of habitat change for these southeastern species. However, one area that still needs additional research is seed germination, particularly, intraspecific and interspecific germination studies. We investigated intraspecific and interspecific seed germination patterns for three Pinguicula species: P. ionantha, P. lutea, and P. planifolia. Seeds from five sites per species were collected in April 2021 in the Florida Panhandle. Two seed germination trials separated by 1.5 mo were conducted. All seeds received a gibberellic acid (GA3) presoak for 24 hr. Overall, significant differences were found in seed germination among species (P. planifolia = P. ionantha > P. lutea) and among sites within a species for P. ionantha and P. planifolia, but not P. lutea. This work provides a foundation for seed germination protocols for these rare Pinguicula species found in the southeastern USA by expanding knowledge of their seed ecology and providing valuable information for conservation efforts of these at-risk species across the region.