Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Equisetum variegatum Schleich. ex F. Weber and D. Mohr

English: Variegated scouring rush, variegated horsetail,

French: Prêle panachée.

Equisetaceae, Horsetail or Scouring rush family.

Published in Deut. Crypt. Gewächse 60: 447. 1807. Bot. Taschenbuch, 60: 447. 1807.

Type: Haller no. 1678 (Hist. Stirp. indig. Helvet. inchoatae 1768), selected by Hauke, Beih. Nova Hedwigia, 8: 80. 1963. Lectotype.

Synonymy. Hippochaete variegata (Schleich.) Bruhin, Verh. Zool.-Bot. Ges. Wien, 18: 760. 1868.

Equisetum variegatum Schleich. f. anceps (Milde) M. Broun Index No. Amer. Ferns 97. 1938.

Vegetative morphology. Plants 6–20 cm high (to 50 cm tall on continental North America); herbs; perennial herbs; not caespitose; never vegetatively proliferating by bulbils on stems or leaves, in inflorescences, from gemmiphores and gemmae, or by fragmentation; jointed fertile stems with pigmentation. Only fibrous roots present. Roots black (or very dark brown). Ground level or underground stems horizontal, or vertical; rhizomatous, or stoloniferous; elongate; 0.5–1.5 mm wide. Ground level or underground stems scales present; 3–8(–12); shiny black; 2–2.5 mm long (shiny black); glabrous. Caudex absent. Aerial stems developed; erect (usually); conspicuously jointed with nodes covered by whorls of tiny leaf teeth fused for part of their length into sheaths that are tipped with teeth (stems unbranched, persisting more than 1 year); filiform (in tiny Arctic plants that look wiry and like E. scirpoides), or not filiform (usually). Aerial stem ridges 3–8(–12); the same number as that of the leaf teeth at each node. Leaves absent or leaf teeth; leaf teeth (in whorls distributed along the stem). Leaf teeth persistence persistent, or marcescent. Leaf teeth 1–3 mm. Leaf teeth 0.5–1.5 mm. Leaf teeth shiny black or brown (very black at the base of the plant, margins often transparent; often membranous at the acute tips when they are young, apices fraying early).

Reproductive morphology. Plants with sporangia, or vegetative leaves without obvious spore-bearing organs (appearing so after the cones are lost in early summer). Sporangia in terminal cone-like structures (stems have chlorophyll: cones have a pointed apex and mature late summer or over winter and shed spores in spring). Aerial stems squarish in cross-section.

Chromosome information. 2n = 216.

2n = 216. Löve in Bir (1960, Iceland); Löve and Löve (1961c, Iceland); Hauke (1993, Fl. N. Amer. 2, secondary reference), and some more southern counts.

Ploidy levels recorded 2x.

Ecology and habitat. Substrates: wet meadows, around the margins of ponds, marshes, along streams, river terraces; imperfectly drained moist areas (or standing water); sand, clay, moss; with low organic content (usually); calcareous. In saturated to poorly drained mineral soil near small ponds (Can 522060); in a wet sedge meadow (CAN 522201); standing water at the edge of a shallow, possibly ephemeral pond (CAN 518566); poorly drained, bare silt of a seepage slope growing in mossy mats (CAN 522712).

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago widespread. Uncommon, rare. Arctic, alpine. Arctic islands: Baffin, Ellesmere, Axel Heiberg, Parry islands (Bathurst), Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William, Southampton, Coats (Boothia and Melville peninsulas).

Northern hemisphere distribution. Circumpolar, or circumboreal (arctic-alpine). Northern Iceland, Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. The subspecies that occurs in the Arctic Archipelago is subsp. variegatum. Subspecies alaskanum occurs on continental North America and is distinguished from subsp. variegatum as follows: sheath teeth, erect, with prominent white margins, subsp. variegatum; sheath teeth incurved, with obscure margins or all black, subsp. alaskanum.

Arctic floras with Porsild as an author have indicated that this species has 6–8 sheath teeth at each node, which distinguishes it from E. scirpoides, which has 3–4 sheath teeth. Hauke (1993, Flora of North America treatment) indicates that E. variegatum may have 3–12 teeth per sheath, in fact overlapping with the values of E. scirpoides. According to Hauke (1993) these taxa are distinguished because in E. variegatum there are as many ridges to the sheaths as there are teeth, while in E. scirpoides there are twice as many ridges as teeth. (The number of ridges can be determined by cutting cross sections of the stem.)

Some authors claim that Schleicher's name of 1797 is a nomen nudum and that it was first validated by Weber and Mohr, Deut. Crypt. Gewächse 60: 447. 1807.

Illustrations. • Habitat. The zone of plants at the point of the arrow is dominated by E. variegatum. Equisetum arvense is more yellow green and common nearby. Baffin Island, Iqaluit, in front of Arctic College. 16 August, 2006. Aiken. CAN. • Close-up of older stems and leaves. Note jointed stems that are marked by a brown ring and white scale-like, old leaves overlapping the node. Nunavut, Ellesmere Island, at Scoresby Bay, 79°53'N, 71°33'W. Aiken 98–018. CAN. Photograph by Mollie MacCormac. • Close-up of base of plant. Base of plants showing very black scales that are shiny under direct light. Nunavut, Mistake Bay, 62 5'N, 93°6'W. CAN 4064. • Close-up of nodes. Leaf teeth with transparent margins, unlike Equisetum arvense, which has solid, black teeth. Nunavut, Baffin Island, Lower Savage Islands. CAN 583028. • Young cone. Node with scale leaves that have wide membranous margins, and a very young cone already more than 3 mm long. • Cone that has shed spores. Cone nearly 1 cm high with dark sporophylls spreading. On some, the pale yellow remains of sporangia that hang from the undersurface are visible. Note broad membranous margins on the scale-like teeth subtending the cone. • Contrasting stems. Equisetum variegatum (left) stems that usually have more stem ridges and are larger in diameter than E. scirpoides (right). Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Sørkapp Land, Sunder Kistefjell. 21 August, 1920. J. Lid 112. O 205227. With permission of the Botanical Museum, University of Oslo, Norway. • Arctic Island Distribution.


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.

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