Equisetum variegatum Schleich. ex F. Weber and D. Mohr
Variegated scouring rush, prêle panachée.
Equisetaceae, horsetail family.
Bot. Taschenbuch 60: 447. 1807.
Hippochaete variegata (Schleich.) Bruhin, Verh. Zool.-Bot. Ges. Wien 18: 760. 1868.
Type: Haller no. 1678 (Hist. Stirp. indig. Helvet. inchoatae 1768) lectotype, selected by Hauke, Beih. Nova Hedwigia, 8: 80. 1963.
Equisetum variegatum var. anceps Milde
Vegetative morphology. Plants perennial herbs; 6–20(–48) cm high (further south); tufted, with ascending, freely branched, rather stiff, straight stems that persist more than one year. Roots black (or very dark brown). Ground-level or under-ground stems horizontal, or vertical and often branched; rhizomatous, or stoloniferous; elongate; 0.5–1.5 mm wide. Scales present; 3–8(–12); 2–2.5 mm long (shiny black); glabrous. Aerial stems erect (usually); conspicuously jointed with nodes covered by whorls of tiny leaves fused for part of their length into sheaths that are tipped with teeth; filiform (in tiny Arctic plants that look wiry and like E. scirpoides), or not filiform (usually); circular or oval in cross-section; with 3–8(–12) ridges (the same number as that of the sheath teeth at each node); glabrous. Branches branches absent. Leaves present and green; leaves distributed along the stems; leaves whorled (on unbranched stems that persist more than one year); leaves evergreen, or marcescent. Petioles absent. Leaf blade bases truncate (into a fused sheath). Blades 1–3 mm long; 0.5–1.5 mm wide. Blades appressed to the stem; membranous (often black at the base and with prominent white margins); straight; lanceolate (broadly), or triangular; flat; appearing single-veined, or with inconspicuous veins. Blades adaxial surface glabrous. Blades abaxial surface glabrous. Blade margins glabrous (margins and transparent). Leaf apices acute (often membranous at the tips and fraying early).
Reproductive morphology. Plants with sporangia, or only vegetative (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 overwinter and shed spores in spring).
Chromosome information. 2n = 216. 216 Löve in Bir (1960 Iceland); Löve and Löve (1961c Iceland); Hauke (1993, Fl. N. Amer. 2, secondary reference). Some more southern counts. Ploidy levels recorded 2x.
Distribution. Northern hemisphere distribution: circumpolar. Yukon, Northwest Territories Islands, Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. Arctic, or alpine. Range in the Canadian Arctic Archipelago widespread. Arctic Islands: Baffin, Ellesmere, Axel Heiberg, Parry Islands (Bathurst), Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William (Boothia and Melville Peninsulas).
Ecology and habitat. Substrates: wet meadows, around the margins of ponds, marshes, along streams, river terraces; imperfectly drained moist areas (or wet); calcareous; sand, clay, moss; with low organic content (usually). Habitats: In saturated to poorly drained mineral soil near small ponds (Can 522060); in wet sedge meadow (CAN 522201); standing water at the edge of a shallow, possibly ephemeral pond (CAN 518566); poorly drained, bare silt of seepage slope growing in mossy mats (CAN 522712).
Notes. Arctic floras with Porsilod as an author, have indicated that this species has 6–8 sheath teeth at each node which distinguishes it from E. scirpoides that has 3–4 sheath teeth. Hauke (1993) indicates that E. variegatummay have 3–8(-14) ridges to the stem so that the numbers for this species overlap those for E. scirpoides . Hauke (1993) indicated that the taxa may be distinguished because in E. variegatum there are and as many ridges to the sheaths as there are theet, 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). Because E. variegatum plants may have 3–14 sheath teeth at each node some specimens of E. variegatum have been incorrectly assigned to E. scirpoides. The subspecies that occurs in the Arctic Archipelago is subsp. variegatum. Subspecies alaskanum that occurs on continental North America and is distinguished from subsp. variegatum on sheath teeth characters. Sheath teeth, erect, with prominent white margins, subsp. variegatum; sheath teeth incurved, with obscure margins or all black, subsp. alaskanum.
Illustrations. • Vegetative stem branching. Plant separated from associated moss to show ground-level and above ground branching and jointed stems. Note that the first internode of each branch is longer than the subtending node. Nunavut, Ellesmere Island, near John Richardson Bay 80°21'N, 71°21'W. Aiken 98–042. CAN. Photograph by Mollie MacCormac. • Plants in mossy habitat. Wiry, high Arctic plants that were growing on a wet seepage slope, Sample removed to adjacent drier ground for the photograph. Nunavut, Ellesmere Island, Scoresby Bay 79°53'N, 71°33'W. Aiken 98–018. CAN. Photograph by Mollie MacCormac. • Close-up of older stems and leaves. Close-up to show jointed stems that are marked by a brown ring and white scale-like, old leaves overlapping the node. Plants growing on Ellesmere Island, Nunavut, at Scoresby Bay 79°53'N, 71°33'W. Aiken 98–018. CAN. Photograph by Mollie MacCormac. • Plant root. Plant with long, healthy root. Plant was teased out of deep moss, in very moist habitat. Nunavut, Ellesmere Island, near John Richardson Bay 80°21'N, 71°21'W. Aiken 98–042. Photograph by Mollie MacCormac. • Close-up of base of plant. Base of plants showing very black scales that are shiny under direct light and nodes with three teeth (visible), the tips of which are transparent. Nunavut, Savage Islands. CAN 583028. Scale in cm. • Base of plant. In some lights the scales at the base of the plant shine. Note the sheaths with teeth that are transparent at the tips. Nunavut: Rankin Inlet. CAN. 365029. • Contrasting stems. Left. Equisetum vagietatum 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 Aug. 1920. J. Lid. 112. O 205227 With permission of the Botanical Museum University of Oslo, Norway. • Arctic Island Distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
