Spore morphology of the genus Dryopteris Adans. (Dryopteridaceae) in Korea

Abstract

Spore morphology of the Korean members of the genus Dryopteris was examined by scanning electron microscopy. In particular, spores of D. hangchowensis, D. woodsiisora, D. saxifragivaria, and D. subexaltata were examined here for the first time. Three perispore types were recognized on the basis of the shape of macro-ornamentations on perispore: these include rugate, echinate, and spinose. The rugate perispore type appeared to be the most common in the genus, and probably represents plesiomorphic condition in the genus Dryopteris. The echinate perispore type is found in D. expansa, and spinose perispore type in D. formosana. The results of this study demonstrate that the perispore characteristics, particularly the shape of macro-ornamentation and surface texture, have diagnostic value at the species level. Indeed, most of the Dryopteris taxa in Korea could be distinguished by their perispore characters. In addition, spores of sexual diploid individuals of D. saxifraga were much smaller than those of agamosporous triploid individuals, supporting the contention that the size of spores in ferns is generally related to ploidy levels.