Eriophorum vaginatum L. s.l.
Cyperaceae, sedge family.
Sp. Pl. 52. 1753
Eriophorum vaginatum var. spissum (Fern.) Boivin
Eriophorum spissum Fern.
Eriophorum spissum var. erubescens (Fern.) Fern.
Plants caespitose; forming large compact tussocks that sometimes die off towards the centre; less than 15 cm high, or more than 15 cm high; (10–)15–40(–80) cm high. Roots pallid-brown. Ground-level or under-ground stems not developed horizontally or vertically underground. Scales absent. Aerial stems erect; not filiform; triangular in cross-section, or circular or oval in cross-section; glabrous. Leaves distributed along the stems. Petioles absent. Sheaths persisting; forming a conspicuous build up at the base of the plant; greyish brown, or reddish (or pale orange brown); with the margins fused to the apex; glabrous; collars collars absent. Ligules present; 0.3–1 mm long; membranous (often turning pale brown); glabrous; ovate-oblong, or transversely oblong; apices acute, or obtuse; entire. Blades 50–150 mm long; 0.6–1.2 mm wide; appressed to the stem, or spreading from the vertical; straight; linear; triangular in cross section; with parallel veins; midvein similar in size to other veins in the leaf; adaxial surface glabrous, or scabrous. Leaf margins glabrous (usually, sometimes scaberulous towards the tip). Leaf apices acuminate.
Flowering stems conspicuously taller than the leaves; with leaves (not closely associated with the apex); uppermost leaf arising below the middle of the stem, or arising above the middle of the stem; glabrous. Flowering culm nodes not exposed. Leaf or reduced bract closely associated with the base of the inflorescence absent. Inflorescences spicate; inflorescence dense; inflorescence globose or subglobose; inflorescence 1.5–5.5 cm long; inflorescence 10–35 mm wide; inflorescence a single spike. Individual spike(s) erect. Bisexual spike(s) with empty bracts at the base. Terminal spike with both sexes in each floret. Flowers sessile or subsessile. Floral scales pale grey; with margins paler than body of scale (spreading at maturity); acute; 7–14 mm long; 2–4 mm wide; glabrous. Perianth represented by bristles; bristles silky white, or translucent. Anthers 1.6–3 mm long. Carpels syncarpous. Stigmas per style 3. Placentation basal. Fruit surrounded by perianth persisting as bristles; an achene (broadly obovate); 1.1–1.4 mm long; black, or brown (grey). Achenes trigonous.
Chromosome information. 2n = 58.
Distribution. North American. Arctic. Range in the Canadian Arctic Archipelago widespread. Common. Arctic Islands: Baffin and Parry Islands (Melville), Banks, Victoria, and Southampton.
Ecology and habitat. Substrates, hummocks (with heath), around the margins of ponds, marshes (along the edges), tundra; aquatic, imperfectly drained moist areas, dry; calcareous; with high organic content. Found in wet meadows with Carex and Eriophorum. In shallow water at the edge of pools, it can be found with Hippurus vulgaris and Ranunculus pallasii. On drier tundra, it is associated with mosses, heath, and lichens.
Notes. The role of E. vaginatum in methane flux from boreal peatlands was studied by Pullman et al. (1995).
A study of the effects of variable soil oxygen and nutrient availability of E. angustifolium and E. vaginatum was done by Gebauer et al. (1995) near Toolik Lake, Alaska. It was shown that whole-plant growth in E. vaginatum improved in flooded soils, but only when nitrogen availability was high. In areas of low nitrogen availability, growth was reduced by 20% compared to growth in drier more aerobic soil.
The roots of E. vaginatum have been shown to have the ability to absorb free amino acids as well as inorganic nitrogen (Chapin III et al., 1993). This is the first documented example of a non-mycorrhizal plant with this capability. Such an adaptation is highly advantageous in the Arctic where inorganic nitrogen is often limiting. Factors regulating the uptake of ammonium and glycine in the field were investigated by Leadley et al. (1997). Nitrogen supply rate was found to be more important than soil factors (buffer capacity and diffusion coefficient), root density, or root uptake kinetics.
Moorhead et al. (1993) modelled the relative contributions of phosphatases associated with the living roots of E. vaginatum and phosphatases associated with soil microbes to the phosphorus released from the substrate within the tussocks of the plant. They found that the former contributed 4% of the total phosporus released, but that this amount was almost twice the annual demand for the plant. Thus, E. vaginaturm may obtain a significant amount of phosphorus from the activity of root surface phosphatase. They also found that 28% of the phosphatase activity occurred during a brief period of time in autumn when substrate availability was high. Since maximum growth occurs early in the year, E. vaginatum must draw on reserves from the previous year to sustain growth.
Porsild (1957) considered Eriophorum vaginatum subsp. vaginatum a western species; east of the 100th meridian it gradually passes into subsp. spissum. In FNA it is treated as subsp. vaginatum (western-northern) and subsp. spissum (eastern-southern) but there is much overlap.
Illustrations. • Plant in habitat. Two tussocks of previous seasons leaves. This season's inflorescences are developing. N.W.T., Banks Island in Aulavik National Park, near green cabin, June 29, 1999. Susan Aiken 99–009, CAN. • Close-up of plant. Close-up of the plant with an accumulation of sheaths at the base and a pre-anthesis inflorescence. Collected Nunavut, Baffin Island, Koukdjuak River, 5 miles north of Kimmirut (Lake Harbour), J.D. Soper, 125749, 25 June, 1931, CAN 28392. • Close-up of plant. Close-up of the plant with an accumulation of sheaths at the base and a post-anthesis inflorescences with lead gray scales. Collected Nunavut, Southampton Island, vicinity of Salmon Pond, 64 12 N, 85 W. G.R. Parker, SP-70–158, 1970. CAN 368132. • Inflorescences. Single head inflorescence covered with spent anthers. N.W.T., Banks Island in Aulavik National Park, near green cabin, June 29, 1999. Susan Aiken.99–009, CAN. • Arctic Island distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L.Consaul, R.L. Boles, R. Elven and M.E. LeBlanc. 2001 onwards. Flora of the Canadian Arctic Archipelago. Volume 1. Pteridophytes and Monocotyledons: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 16th March 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).
