Cryptic characteristics distinguish diploid and triploid varieties of Pteris fauriei (Pteridaceae)

Sporophytes of Pteris fauriei var. fauriei and P. fauriei var. minor were difficult to distinguish based only on the morphology of mature fronds. However, we found the two varieties can be distinguished based on spore size, the number of spores in each sporangium, the number of sperm in each antheridium, antheridium size, reproductive behavior, and the morphology of juvenile sporophyte embryos and fronds. Using spore size, the specimens of P. fauriei var. fauriei and P. fauriei var. minor collected by Père Urbain Faurie in 1904, and published by Hieronymus (1914), are triploid and diploid, respectively.