Athyrium distentifolium subsp. americanum (Maxon) Hult.
FamilyAthyriaceae — APG family: Athyriaceae
SynonymsAthyrium americanum Maxon., Athyrium alpestre var. americanum Butt.
DescriptionRhizome chafly, forming large crown; fronds in vaselike clumps; stipe scaly, low- est primary segments shorter than middle segments.
EcologyWet, rocky slopes, with preference for calcareous soil. A. distentifolium described from Bohemia, subsp. americanum from North America.
The Alaskan plant differs from the European plant in having generally more dis- sected fronds, with ultimate segments more widely separated; it is therefore re- garded as a subspecies, subsp. americanum, and is apparently rare. The plant has long been known as A. alpestre (Hoppe) Rylands, a name antedated by A. alpestre Clairv. Circumpolar map indicates range of entire species complex.
Hultén's Flora About

This is a digital representation of Eric Hultén’s ‘Flora of Alaska and Neighboring Territories: A Manual of the Vascular Plants’, which was published by Stanford University Press in 1968. The book was digitized by C. Webb (at UAMN) as part of the Flora of Alaska project, with funding by the US NSF (Grant 1759964 to Ickert-Bond & Webb), and with permission of Stanford University Press. Data and images © 1968 Board of Trustees of the Leland Stanford Jr. Univ. Usage licence: Creative Commons BY-NC-SA 4.0. NB: You may find OCR errors; please refer to the hard-copy if in doubt.