Hierochloë pauciflora R. Br.
Chlor. Melvill. 35. 1823.
Anthoxanthum arcticum Veldkamp in Schouten and Veldkamp, Blumea 30: 349. 1985.
Type: Canada. Melville Island, 1819–1820, Mr. Beverly, on W.E. Parry's first voyage. (Holotype: BM!).
Hierochloë pauciflora f. setigera E. Lepage, Nat. Canad. 81: 256. 1954. Type: Canada. Ontario: Cape Henrietta, 10 Aug. 1953, A. Dutilly and E. Lepage 31124. (Holotype: CAN!).
Plants not caespitose; with single unbranched stems; less than 15 cm high, or more than 15 cm high; 5–26 cm high. Ground-level or under-ground stems horizontal; rhizomatous; elongate, or compact; 0.3–1 mm wide. Scales present; smooth; 10–20 mm long; glabrous. Aerial stems erect (appearing tiny and delicate); glabrous. Leaves distributed along the stems. Sheaths with the margins fused only in the lower part; glabrous. Ligules 0.4–1.3 mm long; membranous (on uppermost leaves or underdeveloped leaf blades; a fringed membrane on lower leaf blades); glabrous, or hairy; ovate-oblong; apices obtuse; entire. Blades 20–55 mm long; 0.7–2 mm wide (rolled width); appressed to the stem, or spreading; rolled in bud; involute (but easily twisting to appear conduplicate in a wet cross section); midvein similar in size to other veins in the leaf. Blades adaxial surface hairy. Blades abaxial surface glabrous.
Flowering culm nodes not exposed. Flag leaf sheaths inflated. Inflorescence paniculate (sometimes reduced and spike-like); dense (compact); linear; 1–3 cm long; 3–5 mm wide. Inflorescence. Inflorescence main axis glabrous. Number of inflorescence branches at lowest node 1. Inflorescence primary branches 0.5–12 mm long; glabrous; with appressed secondary branches. Spikelets. Spikelets pedicellate; disarticulating above the glumes; laterally compressed; ovate, or obovate; 3.5–6 mm long; 2–4 mm wide. Florets per spikelet 3 (the 2 lower staminate, the terminal spikelet hermaphrodite). Glumes. Glumes shiny, cuneate. First glume 0.8–1 × the length of the second glume; 0.75–0.85 × spikelet length; 2.9–4.6 mm long; lanceolate; glabrous; margins glabrous; veins 1; apex acute. Second glume as long, or longer than the spikelet; almost as long as, or longer than, the lowest floret; lanceolate, or ovate; 3.5–4.7 mm long; glabrous; veins 3. Rachilla internode 0.1 mm long; glabrous. Rachilla not pronounced between the florets; terminating in a well-formed floret. Callus differentiated, or not differentiated (sometimes there are a few sparse callus hairs at base of staminate florets); hairs shorter than the floret. Lemmas. Lemma 2.9–4.4 mm long; lanceolate; rounded on the back; surface dull; surface hairy (at apex); surface with trichomes on and between the veins; veins 3–6. Lemma apex acute; entire; ciliate (very sparsely); awnless (or awns on staminate florets to 1 mm long). Palea well developed; 2.4–3.2 mm long; with hairy veins. Perianth reduced to lodicules. Anthers 1.5–3 mm long. Styles 2. Fruit sessile. Fruit dry; indehiscent. Fruit 2.5 mm long. Seeds 1.
Chromosome information. 2n = 28 (Löve and Löve 1975, 4 records).
Distribution. Amphi-Beringian (not on Greenland or in Scandinavia). High arctic. Arctic Islands: Baffin, Devon, Ellesmere, Parry Islands, Banks, Victoria, Somerset, King William, Southampton, Coats.
Ecology and habitat. Substrates: wet meadows, hummocks, around the margins of ponds, marshes, river terraces, tundra, ridges; imperfectly drained moist areas, on seepage slopes; calcareous (but not necessarily so); rocks, sand, silt, till, moss; peat (sometimes in Sphagnum). Habitats: Growing on wet peaty soils, on fluvial deltas and lowlands. When it is present in the high Arctic it occurs in areas underlain by carbonates and it is exclusively rooted in thick, mossy, mats particularly of Drepanocladus species. In the low Arctic it occurs with Sphagnum and in wet tundra.
Taxon as an environmental indicator. This tiny, delicate grass, is easily out competed by other species. It is indicative of acidic, wet peaty soils with vegetation cover usually less than 15 cm high.
Notes. This tiny grass often occurs as single plants and is easily overlooked. Schouten and Veldkamp (1985) transferred this species to the genus Anthoxanthum as A. arcticum Veldkamp but this has not been widely taken up.
Illustrations. • Habitat. Small purplish and white inflorescences with other grasses and willow in a disturbed area. Nunavut, Victoria Island, Cambridge Bay. Beside weather station at airport. 69°7'N, 105°7'W. elevation 15–20 metres. 20 July 1997. L.L. Consaul 1101 & L.J. Gillespie. CAN. • Plants in habitat. Isolated plant in a cotton grass (Eriophorum angusitfolium) meadow. Banks Island, Aulavik National Park, July, 1999, Aiken 99–045. CAN. Scale bar in cm. • Close-up of young inflorescence. Young inflorescence with uppermost flower opening, white feathery stigmas that appear receptive, and developing preanthesis purple anthers. • Close-up of inflorescence. Complete inflorescence in which the uppermost spikelets have the two stigmas exposed, and the lowermost spikelets are at anthesis with exposed anthers on long filaments. Nunavut, Victoria Island, Cambridge Bay. L.L. Consaul 1101 & L.J. Gillespie. CAN. • Holotype specimen. Plants 10–15 cm tall, with single culms and inflorescences with fewer than 10 spikelets. Canada, Melville Island, 1819–1820, Mr. Beverly on W.E. Parry's first voyage. (Holotype: BM). • Holotype, f. setigera. Hierochloë pauciflora f. setigera. Ontario, James Bay, Cape Henrietta Maria, 1953, A. Dutilly and E. Lepage 31124. (Holotype: CAN). • Distribution map.
Cite this publication as: ‘S.G. Aiken, L.L. Consaul, and M.J. Dallwitz. 1995 onwards. Poaceae of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 10th December 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).
