Woodsia R. Br.
Cliff fern, named for the English botanist Joseph Woods.
Polypodiaceae, fern family.
R. Brown, Prodr., 158. 1810.
Plants caespitose (loosely clustered); usually growing on rock, with stems compact to creeping and with erect to ascending unbranched, but rarely horizontal, fronds arising close together, from a cluster of persistent petiole bases; less than 15 cm high; 1–15(–20) cm high. Roots black. Ground-level or under-ground stems horizontal; stoloniferous; compact. Leaves mostly basal (from the ground-level stems); alternate; compound. Petioles glabrous, or hairy; hairs more than the diameter of the petiole (or glabrous). Blades 30–150(–250) mm long; circinate when young (becoming linear or lanceolate mature fronds); with inconspicuous veins; adaxial surface glabrous, or hairy. Blades abaxial surface glabrous, or hairy. Conspicuous hydathodes present (slit-like), or absent (not visible). Plants reproducing by spores borne in sporangia. Sori with a distinct indusium. Indusia of narrow hair-like segments, one row of cells many times longer than wide, and longer than the sporangia.
Chromosome information. 2n = 78, 82, and 160 (probably).
Distribution. Circumpolar. Arctic, or low arctic, or alpine.
Notes. Woodsia is a well marked genus of ferns, with a base chromosome number of (X =39– 41). The genus Cystopteris is probably the closest relative. Woodsia is distinguished by articulate bases to the petioles and the accumulation of petiole bases that have broken off below the articulation. The veins of the pinnae are obscure, and end in slit-like hydathodes before reaching the leaf margins. The indusia are multilobed and the indusial segments are each a single row of cells that are much longer than wide. The Arctic Woodsia show close affinities to species found only in Eurasia (Windham 1993).
Cite this publication as: S.G. Aiken, M.C. LeBlanc, and M.J. Dallwitz 2000 onwards. Pteridophytes of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval.’ Version: 23rd February 2001. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000) , and Aiken, Dallwitz et al. (1999) should also be cited (see References).