Flora of the Canadian Arctic Archipelago
English: Fern and fern-allies, scouring rushes, and club mosses.
Equisetaceae, Horsetail or Scouring rush family, Lycopodiaceae, Club moss family, Dryopteridaceae, Fern family.
Vegetative morphology. Plants 1–20(–100) cm high; perennial herbs; caespitose, or not caespitose; sometimes vegetatively proliferating from gemmiphores and gemmae, or never vegetatively proliferating by bulbils on stems or leaves, in inflorescences, from gemmiphores and gemmae, or by fragmentation; jointed fertile stems without pigmentation, or with pigmentation. Only fibrous roots present. Roots pallid-brown, or red-brown, or grey, or black. Ground level or underground stems horizontal, or vertical, or absent; rhizomatous, or stoloniferous; elongate, or compact; 0.5–3 mm wide. Ground level or underground stems scales present, or absent. Aerial stems developed, or not developed, fern leaves with long petioles arising from a rhizome; erect, or prostrate; not conspicuously jointed (club mosses and ferns), or conspicuously jointed with nodes covered by whorls of tiny leaf teeth fused for part of their length into sheaths that are tipped with teeth (scouring rushes); filiform (rarely), or not filiform. Aerial stem ridges 0–12. Leaves present, or absent or leaf teeth; mainly basal (ferns), or distributed along the stems; alternate (ferns and club mosses), or whorled (scouring rushes); persistent, or dying annually and non-persistent, or marcescent. Petioles present, or absent. Leaf blades simple (club mosses and scouring rushes), or compound. Blades 5–170 mm long, appressed to the stem or spreading or reflexed (or not applicable), straight (club mosses and scouring rushes) or circinate when young (ferns). Blade adaxial surface with sessile glands or without sessile glands, glabrous or hairy. Blade abaxial surface glabrous or hairy or scaly, hairs sparse or very dense (if applicable). Blade margins entire or glandular-dotted, glabrous; apices acuminate, or acute, or obtuse.
Reproductive morphology. Plants with sporangia, or with gemmae, or vegetative leaves without obvious spore-bearing organs. Sporangia in the axils of unmodified leaves (Huperzia), or in terminal cone-like structures (Equisetaceae and some Lycopodiaceae), or in sori on the undersurface of the leaves (Dryopteridaceae). Aerial stems circular or oval in cross-section, or squarish in cross-section.
General notes. Pteridophytes are represented by 11 species, one with two subspecies, in our area. Most genera of pteridophytes have high basic chromosome numbers, compared with seed plants and bryophytes (Wagner and Wagner 1980). This has been interpreted by some authors as evidence of ancient polyploidy (paleopolyploidy) in the evolutionary lineages. Allozyme studies of ferns and other pteridophytes with high basic chromosome numbers reveal only diploid levels of isozyme gene expression. Therefore, either the hypothesised paleopolyploidy is incorrect or, if correct, most duplicate genes have become silenced, resulting in genetic diploidisation (Soltis and Soltis 1988). Wagner (1992), in a study of the cytology of Lycopodium, assumed that the high chromosome numbers represent repeated polyploidisation of ancestral low numbers and provided a table estimating what the base numbers may be.
This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.
Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.
Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa..