Fossombronia alaskana, a New Hepatic from Arctic Alaska

Abstract

alaskana Steere & Inoue is described as new from arctic Alaska, where it occurs in widely separated localities, all in the Brooks Range or in its northern foothills, extending from Cape Thompson at the western end eastward to Peters Lake, near the Canadian boundary. Its highly specialized habitat is fine silt extruded as boils, which are bare areas in the tundra produced by frost action, and it clearly belongs to a now well-substantiated circumpolar arctic floristic element; its discovery in other arctic areas, such as northernmost Canada and Siberia, can therefore be anticipated. alaskana stands closest probably to F. foveolata Lindb. in its spore markings, but differs from that and all other described species in the firmly closed, angled, and sometimes horned pseudoperianth, which opens only when the capsule is pushed out by the elongation of the seta; as well as in the spores, which may have 7-9 meshes across the convex face, or parallel lamellae with no meshes. The genus Raddi includes approximately 80 described species (Bonner, 1965), most of which are not well understood except for the species in Europe (Miiller, 1954), North America (Frye & Clark, 1937), and Japan (Inoue, 1973). The vast majority of species of occur in tropical and temperate regions of both hemispheres, but become increasingly and rapidly fewer toward the poles. The previously published northernmost station of this genus in North America appears to be that reported by Persson and Weber (1958), who listed Fossombronia sp. from Mt. McKinley National Park, Alaska. They noted that the specimen, though well developed and unmistakeably belonging to Fossombronia, is sterile. Fortunately, we were able to borrow this collection for study from the Cryptogamic Herbarium of the University of Colorado, through the courtesy of Prof. William A. Weber. This specimen (Viereck 10359A; on gravel of a small open frost boil area, gravel bar, north bank of McKinley River, south of Wonder Lake, 1,800 ft. alt., 63o25' N. Lat., 150o55' W. Long.; 23 August 1958) is labelled Fossombronia foveolata Lindb. c. fr. Det. Weber, 1958. Although we were unable to find sporophytes in the rather sparse material 1 For grants in support of field investigations during nine seasons in arctic Alaska between 1951 and 1973, the senior author thanks the Office of Naval Research, the National Science Foundation, and the Arctic Institute of North America; this paper was completed with support of a current grant from the National Science Foundation to the New York Botanical Garden (GB-32004X). Grateful acknowledgement is also made, with special appreciation for unstinted logistic and other support given by them, to the several directors of the Arctic Research Laboratory (now the Naval Arctic Research Laboratory) at Point Barrow, Alaska, notably Ira L. Wiggins, Max Brewer, and John Schindler. 2 New York Botanical Garden, Bronx, New York 10458. 'National Science Museum, Hyakunin-cho, Shinjuku, Tokyo 160, Japan. This content downloaded from 157.55.39.197 Sun, 11 Dec 2016 04:34:08 UTC All use subject to http://about.jstor.org/terms 64 THE BRYOLOGIST [Volume 77