From Natural History of Southeast Alaska
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Four species in the region, with 3 of them widespread.

Sitka Rockbrake (Cryptogramma sitchensis) and American Rockbrake (Cryptogramma acrostichoides) are quite similar and can be a challenge to tell apart. The matter is complicated somewhat by the occurrence of infertile hybrids between the two species.

Family: Pteridaceae

Group: Vascular Plant, Species

Scientific NameCommon NameSummary
Adiantum aleuticumMaidenhair FernPerennial fern with fan-shaped delicate fronds common on wet cliffs and forested wet areas, especially on slopes and rocky areas. Expected throughout the region, except possibly the far northern parts (FNA map), this species has been collected (in Arctos as A. pedatum) widely throughout the region south of Juneau and Icy Strait, though most collections appear to be from islands.
Cryptogramma acrostichoidesAmerican RockbrakeExpected throughout the region (FNA map). Collections have been made from scattered locations throughout. Hybrids with C. sitchensis may occur.
Cryptogramma sitchensisSitka RockbrakeExpected throughout the region (FNA map), most collections in the region appear to be from the northern half. (Whether this is due to differences in frequency or an artifact of sampling effort is unclear.) Appears to reach the southern extent of its distribution in North America in the region.
Cryptogramma stelleriFragile RockbrakeExpected throughout the region on sheltered calcareous cliff crevices and rock ledges (FNA map), there are apparently very few collections in the region. One from northern Prince of Wales Island was described as being found "in narrow crevice of limestone, near base of cliff, well-shaded"