- Group 1Lycophytes, Monilophytes
- Group 2Gymnosperms
- Group 3Monocots
- Group 4Woody angiosperms with opposite or whorled leaves
- Group 5Woody angiosperms with alternate leaves
- Group 6Herbaceous angiosperms with inferior ovaries
- Group 7Herbaceous angiosperms with superior ovaries and zygomorphic flowers
- Group 8Herbaceous angiosperms with superior ovaries, actinomorphic flowers, and 2 or more distinct carpels
- Group 9Herbaceous angiosperms with superior ovaries, actinomorphic flowers, connate petals, and a solitary carpel or 2 or more connate carpels
- Group 10Herbaceous angiosperms with superior ovaries, actinomorphic flowers, distinct petals or the petals lacking, and 2 or more connate carpels
Hybridization has been an important force in Polypodium. It has led to the formation of several allopolyploid species, including our P. virginianum (the hybrid-derived species from P. appalachianum and P. sibiricum Sipl.). Though hybridization continues to be an important source of confusion, variation within the species is the major hurdle to understanding the identity of our taxa. Collectors are encouraged to gather reproductive specimens so that spore condition can be observed (fertile vs. abortive). The species show monomorphic and slightly lustrous spores compared with the nothospecies, which has highly polymorphic and dull spores. Reference: Haufler et al. (1993b).
Show photos of: Each photo represents one species in this genus.