Flora of the Canadian Arctic Archipelago
Lycopodiaceae, Club moss family.
Vegetative morphology. Plants (1–)2–14 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. Only fibrous roots present. Roots pallid-brown. Ground level or underground stems horizontal, or absent; rhizomatous, or stoloniferous (or not applicable); elongate (when present); 0.5–3 mm wide. Ground level or underground stems scales absent. Aerial stems erect. Aerial stem ridges 0, or 4. Leaves distributed along the stems; alternate (a contrast with the Equisetaceae); persistent. Petioles absent. Leaf blade bases truncate, or cuneate. Blades 0.2–3.5 mm long, appressed to the stem, straight or somewhat curled, linear or elliptic or triangular, flat, with inconspicuous veins. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blade margins glabrous; apices acute.
Reproductive morphology. Plants with sporangia, or with gemmae. Sporangia in the axils of unmodified leaves (Huperzia), or in terminal cone-like structures. Aerial stems circular or oval in cross-section, or squarish in cross-section.
North American distribution. Range in the Canadian Arctic Archipelago limited. Uncommon, rare.
General notes. Schofield (1989) reported the following information about club mosses. Members of the Lycopodiaceae are "Carboniferous-period survivor[s] that grow in the tropics on other plants in a nonparasitic manner. Despite its name, club moss is not related to moss. It is a vascular plant, with cellular network to transport water and nutrients through its tissues." (p. 108). The strobili yield a yellow powder called "vegetable sulphur" or "vegetable brimstone". "It is often used for diaper rash because the powder is soothing and healing. In addition, it contains a waxy substance that is extremely water-repellant. It is reported that if you coat your hand with club moss powder and submerge it in water it will remain completely dry.... The friction-reducing powder is frequently used as a dusting powder for condoms, a pharmaceutical aid to prevent pills from sticking together, and a body powder for the bedridden. Since this substance is highly flammable (one of its traditional uses was for bright lights for nighttime photographers and theatrical explosives), don't allow club-moss-coated convalescents to smoke in bed! The club moss plant itself is used to stuff pillows as an external application on aching areas,... e.g., "for cramps in the leg"." (Schofield 1989, p. 109).
The Lycopodiaceae s.l. is an ancient and probably monophyletic family without close-living relatives. The family has a virtually cosmopolitan distribution. Estimates of the number of species range from approximately 200 to more than 500 (Øllgaard 1987). Porsild placed all the taxa found in the Canadian Arctic Archipelago in the genus Lycopodium. Extensive research since then has led to several revised classifications of the family.
Øllgaard (1987) proposed a revised classification of the Lycopodiaceae based on branching patterns, cortex and stellar anatomy, distribution of mucilage cavities, leaf differentiation, morphology of sporophylls, sporangia, spores, gametophytes, chromosome numbers, and phytochemistry.
Wagner and Beitel (1992) discussed cytological problems in Lycopodium s.l., pointing out that the most important distinction between members of the family and seed plants has to do with fertilisation. The gametes involved in "selfing" in seed plants arise from two different recombinant products of meiosis, and therefore, selfing does not often produce homozygous offspring. On the other hand, members of the Lycopodiaceae and Equisetaceae have the capacity to produce completely homozygous offspring, since a gametophyte and its gametes are produced from a single haploid spore. This is referred to as intragametophytic selfing.
Wagner and Beitel (1992) provided a generic classification of modern North American Lycopodiaceae based on 50 characters of anatomy, chromosomes, spores, and gametophytes and analysed the data gathered using Wagner's ground-plan-divergence method of cladistics (Wagner 1980). Wagner and Beitel (1992) justified segregating taxa previously treated as being in the genus Lycopodium, finding that the groups they recognised as separate genera have many distinguishing features with strong gaps that separate them from each other. These features include monophylesis, uniquely derived states, inability to hybridise, and a level of segregation consistent and comparable with generic divisions in other Pteridophytes.
Wagner and Beitel (1992) were aware of the work of Josef Holub and Benjamin Øllgaard and recognised that both had made extensive contributions to the knowledge and understanding of the family, including providing two systems of classification (Holub 1983 and Øllgaard 1987). All three authors provide extensive references to the earlier work on the Lycopodiaceae. While Wagner and Beitel (1992) limited their work to North American members of the family they were aware that the classification they proposed was closer to the ranks proposed by Holub (1983). A modified version of a key to the genera for the three genera recognised in the Canadian Arctic follows, based on Wagner and Beitel (1992).
1a. Sporophylls, like other leaves, photosynthetic; plants epiphytic or terrestrial; roots running from the apex through the cortex before emerging; leaves lacking mucilage canals; rhizomes absent; spores foveolate-fossulate; chromosomes x = 67–68 (Sub-family Huperzioideae)
2a. Plants producing specialised lateral bulbils (gemmiphores and gemmae); gametophytes unbranched; spore angles truncate, spore sides concave ... Genus Huperzia Bernh.
1b. Sporophylls more or less strongly modified, unlike other leaves, non-photosynthetic at maturity; plants terrestrial or semiaquatic; leaves with basal mucilage canals; roots emerging immediately, scattered along the rhizomes; spores various but not foveolate-fossulate (Subfamily Lycopodioideae)
3a. Shoots round-branched, the mature leaves monomorphic and separate, in 6–8 ranks; sporangial wall cells with invaginations and evaginations; gametophytes grey or brown, flat, button-like and convoluted when mature; chromosomes x = 34 ... Genus Lycopodium L.
3b. Shoots flat-branched, the leaves mostly dimorphic or trimorphic and overlapping; sporangial wall cells smoothly sinuate; gametophytes orange-pigmented, narrowly top-shaped, non-convoluted; chromosomes x = 23, flat-branched club mosses ... Genus Diphasiastrum Holub.
Illustrations. • Club-mosses. Family has sporangia borne in cones or, as in this case, the axils of unspecialised leaves. Photo Library image S84–5645. • Young cone. Left, young fertile strobilus, or cone-like organ, with yellow sporangia just visible in the axils of the lower sporophylls. Right, sterile stem that has longer leaves. Photo Library image S84–5638. • Old cones. Cone-like strobili that have opened to reveal sporangia borne in the axils of modified leaves. CAN 4701.
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..