At Least Two Evolutionarily Distinct Species within Histiopteris incisa Inferred from Molecular and Morphological Evidence

Histiopteris incisa (Dennstaedtiaceae) is one of the most cosmopolitan species among the leptosporangiate ferns. Based on sequences of the chloroplast rbcL gene, we recognize two lineages within H. incisa, and these differ in scale and leaf morphology. This suggests that at least two evolutionarily distinct species are contained within present circumscriptions of H. incisa.