Leaves flat but involute towards apex, with numerous veins raised on both surfaces, mid vein slightly broader than the other veins; both surfaces densely papillose along veins. Vegetative shoots with leaf arrangement conspicuously distichous; leaves are crowded and pointing to opposite sides, making these shoots unique in appearance among Svalbard grasses, a feature only partly shared by the hybrid species Arctodupontia scleroclada. Leaves of vegetative shoots up to 32 cm long, often much longer than culms of reproductive shoots, in many stands very broad (4—9 mm), in others more narrow (2—4 mm), tapering evenly towards apex. Typically, leaves on floating shoots are narrower than on aerial shoots. Culm leaves (3)4—5, similar to leaves of vegetative shoots but usually much shorter, blades 3—8(9) cm, flag leaf blade attached above middle of culm. Ligula 2—4(5) mm, more or less truncate, deeply lacerate.
Arctophila fulva is closely related to Dupontia fisheri, probably one of the parental genera to the assumed hybrid genus Dupontia, and the genome of Dupontia has been homogenized in the direction of Arctophila (Brysting et al. 2004; Brysting in comments in Elven et al. 2011). The two genera also produces a transgenus hybrid species: Arctodupontia scleroclada. It is often difficult to keep these three genera and species apart. Dupontia and Arctodupontia do not have the coarse, strongly distichous leafy shoots of Arctophila and never as broad leaves as Arctophila (usually 4—9 mm); however, there are narrow-leaved Arctophila, too. The glumes and lemmas of Dupontia are much longer than those of Arctophila, with extended, deeply lacerate apices. For Arctodupontia scleroclada, see that species.
The broad, open panicle of Arctophila may resemble that of some Poa species but the leaves are markedly different: in Arctophila leaves are not keeled but in a dense distichous arrangement on shoots; in Poa leaves are distinctly keeled but rarely in distichous arrangement (the main exception being P. alpina). Also the keeled backs of glumes and lemmas in Poa contrast with the rounded backs in Arctophila. No species of Poa grows as wet as does Arctophila fulva.
Arctophila fulva is always rooted in permanently wet or submerged fine substrates and may form dense swards with innumerable leafy shoots, but often very few flowering shoots, or it has leaves floating on the water (and then usually not flowering). It is indifferent as to soil reaction (pH) but melt water from the permafrost furnishes the wetlands with minerals and ions all summer. The species is found both in calm and slowly running water.
Distributed in the middle and northern arctic tundra zones and the weakly oceanic to weakly continental sections. The species is locally common in the wetlands of Bjørnøya where it is recorded from 14 sites but only found flowering two times (Engelskjøn & Schweitzer 1970). On Spitsbergen there are numerous recorded sites along the west coast and fjords from Sørkapp Land in the south to Liefdefjorden in the north but no records from the Wijdefjorden area or from the east coast. The species is not recorded from any of the other islands in the Spitsbergen group.
Arctophila fulva is one of the ecologically most important wetland vascular plant in the Arctic. It is the major constituent of nearly all larger arctic swamps in NE Europe, N Asia and N North America, also in the northern boreal zone. It is very rare in Greenland and in NW Europe. It has long been known from the Bothnian Bay and the Torniojoki valley in N Sweden and Finland but has comparatively recently also been found in single sites in, respectively, Finnmark in N Norway (in 1980; see Elven & Johansen 1981) and Oppland in S Norway (in 2012; see Elven & Fremstad 2012), in both cases suspected to result from fortuitous long-distance bird dispersal (see Elven et al. 2013).
Arctophila fulva is the only accepted species in its genus but quite polymorphic. It is hexaploid (2n = 42; Elven et al. 2011) and is probably of hybrid origin. The plants on the European mainland in Fennoscandia and in Russia south of the Arctic are often quite tall (100 cm or more) and with a large, pendulous panicle (var. pendulina (Laest.) Holmb., described from the Torniojoki valley along the border between Sweden and Finland). Most people would not recognize them as belonging to the same species as the low-grown Svalbard plants. Plants from arctic Russia are distinctively more low-grown, similar to the plants in Svalbard, and have been described as ssp. similis (Rupr.) Tzvelev (from the arctic island of Kolguev). There are no recent morphological studies of the variation in this species, nor genetic studies, i.e., no consistent support yet for recognition of races. However, the morphological differences between the plants of N Fennoscandia and those of Spitsbergen and Bjørnøya prevent us from assuming a bird dispersal route for this species in that direction. The rareness in Greenland makes dispersal to Svalbard from the west unlikely. The remaining possibility is a dispersal connection between Svalbard and the N Russian areas (i.e., ssp. similis).
Some of the plants on Bjørnøya are unusually coarse, much coarser than anything on Spitsbergen, and resemble the plants on the mainland in N Russia (e.g., the Ponoj area on Kola Peninsula). These may have come to Bjørnøya from another source area than the plants in Spitsbergen and the majority of Bjørnøya plants.
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.
Brysting, A.K., Fay, M.F., Leitch, I.J. & Aiken, S.G. 2004. One or more species in the arctic grass genus Dupontia? – a contribution to the Panarctic Flora project. – Taxon 53: 365–382.
Cayouette, J. & Darbyshire, S.J. 2007. Arctophila (Rupr.) Andersson. – In: Flora of North America Editorial Committee (eds.), Flora of North America north of Mexico. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1: 605–607.
Elven, R. & Fremstad, E. 2012. Hengegras Arctophila fulva funnet i Sør-Norge. – Blyttia 70: 237–243.
Elven, R., Fremstad, E. & Pedersen, O. (eds.) 2013. Distribution maps of Norwegian vascular plants. IV The eastern and northeastern elements. — Akademika Publishing, Trondheim.
Elven, R. & Johansen, V. 1981. Hengegras – Arctophila fulva – ny for Norge. – Blyttia 39: 27–31.
Elven, R., Murray, D.F., Razzhivin, V. & Yurtsev, B.A. (eds.) 2011. Annotated Checklist of the Panarctic Flora (PAF).
Engelskjøn, T. & Schweitzer, H.J. 1970. Studies on the flora of Bjørnøya (Bear Island) I. Vascular plants. — Astarte 3: 1—36.