Graminoid herb with extravaginal branching, growing in often extensive mats due to horizontal, branched rhizomes, typically with branch lengths 5—15(20) cm between shoots. Aerial shoots ascending from rhizome, at base with several brownish prophylls (reduced leaves without or with a short blade). Base of culms with a few withered leaves not forming a sheath. Culms 7—25(50) cm, erect, smooth and glabrous except for occasionally a few hairs at the base of the panicle.

Leaves flat, tapering along their entire length, smooth or slightly scabrous on veins, often with a few hairs apically on the lower surface, with more or less distinct midvein and several lateral veins distinctly raised on the upper surface. Basal leaves 5—10(13) cm long, 3—5(7) mm broad, green. Culm leaves (above the withered basal leaves) usually 2, with strongly inflated sheaths up to 5 mm broad, blades rapidly reduced in length upwards on culms, flag leaf blade 1—3(4) cm or sometimes reduced to a sheath only, attached on the lower 1/3 of culm. Ligula 1—2 mm, obtuse.

The units of the inflorescence of Poaceae are the spikelets, nearly always numerous in a panicle or spike-like inflorescence. Spikelets are composed of 2 glumes (bracts for the spikelet) and one or more flowers (the term used below) or rather floral units, often named ‘florets’ because we do not know what is the exact flower. A flower or floret is composed of a lemma with one mid vein (probably the floral bract), a palea with 2 mid veins (either fused bracteoles or perhaps 2 fused perianth leaves), 3 small organs called ‘lodiculae’ and essential in the opening of the flower at anthesis (possibly transformed perianth leaves or transformed stamens), 3 stamens (mostly), and a gynoecium of 2 fused carpels with 2 feathery stigmas and one seed.

Inflorescence a short, compact, oblong or cylindrical, spike-like panicle 0.8—1.5 × 0.7—1.1 cm. Panicle occupying less than 1/5—1/10 of culms, with numerous nodes and numerous branches at each node. Panicle branches very short (usually less than 3 mm) but with several spikelets (nodes and branches totally covered by spikelets and invisible unless the panicle is dissected). Spikelets ovate, strongly laterally compressed, 3—4 × 1—1.5 mm, 1-flowered. Both glumes similar, 3—4 mm, as long as spikelet, connate at base, ovate, acute, with a marked, blackish keel and folded (convolute) along the keel, with 2 veins besides the keel, grey or greyish green but colour hidden by the dense silky white hairs throughout, sometimes with a very short awn. Lemmas 2.5—3.5 mm, ovate, margins connate for more than half the length, indistinctly 3-veined, green or greyish green and glabrous except for the ciliate keel, with a 2—4(5) mm geniculate awn from the base of its keel and exceeding the lemma by 1—2(3) mm but often hidden in the pubescence. Palea absent or very reduced. Anthers (when well developed, see Comments) 1.3—2.5 mm, intensely red at beginning of flowering.

Fruit an achene (with one seed).

Sexual reproduction by seeds; efficient local vegetative reproduction by clonal growth by rhizomes, probably forming colonies covering hundreds or thousands of m² and fragmenting. Seed production depends on wind pollination and occurs regularly. Seeds collected in 2008 did not germinate (Alsos et al. 2013), whereas seeds collected in 1969 (Eurola 1972) and 2007 (Müller et al. 2011) germinated to low percentages. This is not unexpected as efficient seed reproduction (i.e., resulting in new individuals) must be a very rare event in very long-lived mat-forming plants.

The pedicels break off immediately beneath the glumes and the dispersed units are the entire spikelets, being easily spread by wind and animals due to the long hairs on the glumes. Most panicles of Alopecurus are free of fruits at the end of season.

There is nothing very similar to this species in the native Svalbard flora. The most similar may be Trisetum spicatum with a dense, spike-like panicle. However, Trisetum differs in being a tussock plant with hairy culms, in having a dark grey or blackish panicle with little hairs, and 2—4-flowered spikelets where the glumes are shorter than the lemmas.

The broad leaves of Alopecurus ovatus are similar to those of Arctagrostis latifolia. Non-flowering plants of the two species can be difficult to distinguish; however, Alopecurus has long leaves with short (1—2 mm), obtuse ligulas, whereas Arctagrostis has conspicuously short, broad leaves with long (3—6 mm), often fringed ligulas.

Compared with the rare and ephemeral introduced species of Alopecurus, A. geniculatus and A. pratensis, none of these have the strongly inflated sheaths and the conspicuously hairy panicles of A. ovatus; neither has the introduced Phleum pratense.

Moist meadows, shallow mires, sediment plains, moss tundra. Depends on moisture and usually on fine-grained substrates. Favoured by manuring, and the culms may reach 50 cm (or perhaps even more) in bird-cliff meadows and settlements. Probably indifferent as to soil reaction (pH).

Common in the middle and north arctic tundra zones and reaching the polar desert zone. Common in all sections except the clearly continental one where it seems to be rare. Alopecurus ovatus is known from all major and most of the smaller islands, including Bjørnøya (where it is rather common), Hopen, Kong Karls Land and Prins Karls Forland.

Alopecurus ovatus is circumpolar, mainly in the arctic and north boreal zones, but less frequent in the North Atlantic regions than elsewhere. The species is absent from Iceland, Fennoscandia, and the western parts of North Russia but has isolated occurrences in Scotland. It is monomorphic throughout the major parts of the Arctic, the Beringian regions being an exception where much additional variation is present (see Elven et al. 2011 and Comments).

Alopecurus ovatus belongs to a small species group including one species in southern South America (“Antarctic”), A. magellanicus Lam., and at least three species in the northern hemisphere: the circumpolar A. ovatus, the narrowly amphi-Beringian A. stejnegeri Vasey, and the amphi-Pacific A. glaucus Less. that occurs in mountains in Siberia, the Russian Far East, and W North America. The northern and southern parts of this A. magellanicus group are separated by a wide gap across the tropical and subtropical belts in America. The disjunction between the northern and southern hemisphere plants is probably not recent as the southern plants have an extensive range from Peru south to Tierra del Fuego with two named varieties. Many American authors consider the entire group one polymorphic species. Soreng et al. (2003), followed by Crins (2007), merged the northern hemisphere plants named as A. alpinus sensu Sm., A. borealis, A. glaucus, A. rozhevitzianus Ovcz., and A. stejnegeri with the South American ones under the South American priority name A. magellanicus Lam. These authors were probably not aware of the early name A. ovatus. They did not suggest any racial name(s) for or differentiation among the northern plants; however, their main focus may have been on the southern hemisphere plants.

Soreng et al. (2003) and Crins (2007) did not consider the variation among the northern plants, and we disagree with Crins' conclusion that all the northern variation is part of an environmentally determined continuum. We are not aware of any molecular or morphological support for a merger of the southern and northern hemisphere plants within one species, neither for a merger in the north. We accept that A. magellanicus belongs in this aggregate. We refrain, however, from accepting it as name for the northern plants until the northern and southern hemisphere plants have been more thoroughly compared. We are also reluctant to accept the northern plants as subspecies. Transitional forms between them are rare where their ranges overlap, as they do in Beringia. At present, we therefore find a solution with several species in the north (and one in the south), the best fit with the known morphological variation.

Alopecurus ovatus and its relatives all have high and unstable chromosome numbers in the range 2n = ca. 70—ca. 150. Such numbers are often typical of grasses with asexual seed reproduction (agamospermy). However, such grasses usually also have aborting pollen. We have found the pollen development in most stands of A. ovatus to be normal and assume the species to be sexual. In Svalbard, most stands are found with panicles full of red anthers early during flowering, but we have also observed a few stands with shrivelled, yellow anthers that do not protrude from the panicle. The same is found in the herbarium material. It suggests that some of the chromosome number variation may be reflected in unbalanced numbers resulting in failed meiosis. However, agamospermy has never been suggested from the genus Alopecurus.

The correct scientific name of this plant has been a matter of discussion for quite some time. If we consider the South American name A. magellanicus from 1791 inappropriate, the earliest name is A. alpinus Sm. 1803. This name is based on a Scottish plant and belongs to our species, to which it has been applied until quite recently (e.g., Rønning 1964, 1972, 1979). The name A. alpinus Sm. 1803 is, however, predated by the name A. alpinus Vill. 1786, belonging to and being the valid priority name for an entirely different species in the W Alps. For the last two decades, the name A. borealis Trin. 1820, based on a Beringian plant, has been applied to our plant (e.g., by Elven & Elvebakk 1996; Rønning 1996; Lid & Lid 2005; Elven et al. 2011). We have not had the opportunity to study the type specimen (if any exists, then probably in a Moscow herbarium), but it was collected in a part of Beringia where also the related A. stejnegeri occurs. This possible controversy is probably solved by the re-discovery of the name A. ovatus Knapp 1804 (see References), based on Scottish plants incontestably belonging to our species and predating the name A. borealis Trin. by 16 years. We therefore apply the name A. ovatus for this popular plant, one of the real beauties of the Svalbard nature.

Alsos, I.G., Müller, E. & Eidesen, P.B. 2013. Germinating seeds or bulbils in 87 of 113 tested Arctic species indicate potential for ex situ seed bank storage. – Polar Biology 36: 819–830. Doi 10.1007/s00300-013-1307-7.

Crins, W.J. 2007. Alopecurus L. – In: Flora of North America Editorial Committee (eds.), Flora of North America north of Mexico. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1: 78

Elven, R. & Elvebakk, A. 1996. Part 1. Vascular plants. – In: Elvebakk, A. & Prestrud, P. (eds.), A catalogue of Svalbard plants, fungi, algae, and cyanobacteria. – Norsk Polarinstitutts Skrifter 198: 9–55.

Elven, R., Murray, D.F., Razzhivin, V. & Yurtsev, B.A. (eds.) 2011. Annotated Checklist of the Panarctic Flora (PAF) Vascular plants. http://panarcticflora.org/

Eurola, S. 1972. Germination of seeds collected in Spitsbergen. — Annales Botanici Fennici 9: 149—159.

Knapp, J.L. 1804. Gramina britannica; or descriptions of the British Grasses with remarks and occasional descriptions. — T. Bensle, London.

Lid, J. & Lid, D.T. 2005. Norsk Flora. Ed. 7 by Elven, R. – Det Norske Samlaget, Oslo.

Müller, E., Cooper, E.J. & Alsos, I.G. 2011. Germinability of arctic plants is high in perceived optimal conditions but low in the field. – Botany 89: 337–348. Doi 10.1139/b11-022.

Rønning, O.I. 1964. Svalbards flora. – Norsk Polarinstitutt, Oslo.

Rønning, O.I. 1972. The distribution of the vascular cryptogams and monocotyledons in Svalbard. – Kongelige Norske Videnskabers Selskabs Skrifter 1972–24. 63 pp.

Rønning, O.I. 1979. Svalbards flora. Ed. 2. – Norsk Polarinstitutt, Oslo.

Rønning, O.I. 1996. Svalbards flora. Ed. 3. – Norsk Polarinstitutt, Oslo.

Soreng, R.J., Peterson, P.M., Davidse, G., Judziewicz, E.J., Zuloaga, F.O., Filgueiras, T.S. & Morrone, O. 2003. Catalogue of New World grasses (Poaceae): IV. Subfamily Pooideae. – Contributions from the U.S. National Herbarium 48. 730 pp.