Solitary graminoid herb growing in small, dense tussocks with all branching inside leaf sheaths (intravaginal, i.e., with no runners or stolons). Culms to 15 cm (often much taller outside Svalbard), erect, glabrous, usually scabrous just beneath the inflorescence. Base of shoots surrounded by pale brown to yellowish white sheaths of previous years' leaves. Usually with no prophylls (scaly leaves without a developed blade at base of leafy and reproductive shoots) or sometimes one.

Leaves green or often purplish, filiform, narrowly convolute, with ribs due to sclerenchyma (strings of discontinuous strengthening tissue), smooth or slightly scabrous in margins and along veins. Basal leaves 4–8 cm long, less than 1/2 length of culm (the reason behind the scientific names 'brachyphylla' and previously 'brevifolia', both meaning short leaves), 0.3–0.5 mm broad. Leaf sheaths open. Uppermost culm leaf (the 'flag leaf') blade linear, 0.8–1.7(3.0) cm, attached at the lower 1/3 of the culm. Ligula very short (less than 1 mm).

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 1 mid vein (probably the floral bract), a palea with 2 mid veins (either 2 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 an open, narrow and often interrupted, several-sided, purple panicle 1.8–2.5 cm long, occupying less than 1/4 of culm length. Panicle branches short (usually less than 5 mm), very scabrous, each branch with 1–2(3) spikelets. Spikelets 7–11 × 1.5–2.5 mm (awns included), with 3–4 flowers. Bracts (glumes and lemmas) with rounded backs. Glumes 2.5–4.5 mm, the lower one much shorter than the upper one, acute to acuminate, with 1–3 indistinct veins, glabrous and shiny, the upper glume often with long, slender fringes or hairs in the margin. Lemmas (excluding awn) 3.5–5 mm, with several more or less distinct veins, scabrous, especially in distal part, carrying a 1–3.5 mm very scabrous awn. Paleas scabrous on and between veins. Anthers well developed, 0.5–1.3 mm.

Fruit an achene (with one seed).

Sexual reproduction by seeds; no vegetative reproduction. Wind pollinated. Seed production abundant (R. Elven, observ.) and germination about 46 % (Alsos et al. 2013).

Passive dispersal of fruits inside florets, but the scabrous awn may attach to birds and animals and also facilitate some wind dispersal.

The fescues of Svalbard belong to several groups. The Festuca rubra group is characterized by both intravaginal and extravaginal branching, the latter resulting in rhizomatous mats, and by several prophylls (reduced leaves usually without or with short blades) at the base of the shoots. All the others have intravaginal branching only, resulting in dense tussocks without any runners, and only one or no prophyll. The tussocky species are divided on four groups: Festuca baffinensis, the F. brachyphylla group, F. ovina, and the F. vivipara group. Festuca baffinensis and the F. brachyphylla group are both distinguished from F. ovina (and its more southern relatives) by the short anthers (less than 1.2 mm), whereas F. ovina has anthers of ca. 2 mm). Festuca baffinensis differs from the F. brachyphylla group in its hairy culms and its one-sided dark purple panicle; the others have glabrous culms and many-sided and otherwise coloured panicles. The F. vivipara group differs from the other groups in reproduction by bulbils (vivipary).

Within the Festuca brachyphylla group, F. hyperborea is distinguished by its very short and spoon-shaped blade of the flag leaf (the uppermost leaf on the culm); the others (and especially F. brachyphylla) have an extended blade. Festuca brachyphylla differs from F. edlundiae in its erect culms being scabrous just beneath the panicle; in F. edlundiae the culms usually grows more in lateral direction, are appressed to the ground, and are smooth beneath the panicle, at least in Svalbard. Another difference is that F. edlundiae is glaucous (with a bluish bloom) on leaves and culms and have a pale lilac panicle, F. brachyphylla is green (not glaucous) on leaves and culms, and have an often dark purple panicle.

This species is confined to gravel plains and heath slopes with open patches. All sites are within Tertiary sandstones, i.e., substrates with a circumneutral soil reaction (pH); however, this may be a coincidence due to its restricted range. The substrate is usually moderately coarse (mixed moraine, sand and gravel) and well-drained, in sites with little or early disappearing snow cover.

Festuca brachyphylla is thermophilous in Svalbard and only found in a single, small and continuous, climatically favourable area. It has been found only in the middle arctic tundra zone and weakly continental section in Adventdalen and at Adventfjorden including Longyearbyen (Nordenskiöld Land) at Isfjorden, Spitsbergen, in one of the climatically most favourable parts of Spitsbergen. Here it has a number of sites from Hotellneset in the west to the middle parts of Adventdalen in the east. This restricted range is surprising as F. brachyphylla everywhere else is the most common and widely distributed representative of the group (also in the northernmost zones, see Aiken et al. 1995). These small-grown, tussocky Festuca species have been collected regularly, and it is unlikely that the range is significantly larger in Svalbard than what is currently known. It suggests a single dispersal to the Adventfjorden district on Spitsbergen and subsequent spread, probably during the warmest part of the Postglacial Hypsithermal (7,000–4,000 years ago).

In a circumpolar context, F. brachyphylla is the most widespread of all species in the complex, fairly common throughout all arctic parts of NE European Russia, Siberia, Beringia, Canada, and Greenland. It has been reported from the Murman area (Chernov 1953) but those records are not accepted by Elven et al. (2011).

The Festuca brachyphylla complex includes 3 species in Svalbard, the tetraploids (2n = 28) F. edlundiae and F. hyperborea and the hexaploid (2n = 42) F. brachyphylla (for the tetraploid F. baffinensis, see that species). A diploid (2n = 14) representative of the complex, F. brevissima, is found in Beringia. It is likely that many of its species have a hybridogeneous polyploid origin; however, the evolutionary pathways have not been revealed. The species delimitations were made quite clear by Aiken et al. (1995) and subsequently in Svalbard by Fjellheim (1999), Fjellheim et al. (2001), Guldahl (1999), and Guldahl et al. (2001). These Svalbard studies showed that Rønning's treatment (Rønning 1961, 1972) as F. brachyphylla and F. hyperborea was untenable, like most other previous studies of the group (and especially Alexeev's in Russia, see, e.g., Alexeev in Tolmachev et al. 1995). These authors tried to fit three distinct species into a two-species model (F. brachyphylla–F. hyperborea). Guldahl et al. (2001) argued that especially F. brachyphylla was enzymatically similar to N Scandinavian F. ovina (diploid, 2n = 14) and that the polyploids in the F. brachyphylla complex might possibly track back (evolutionary through allopolyploidizations) to diploids in the F. brachyphylla complex, especially to Beringian F. brevissima, and to the F. ovina complex (several species in Europe and N Asia).

The first record of F. brachyphylla in Svalbard is due to the observant Czech botanist Emil Hadač in 1939 when he identified a plant he found in Adventdalen as F. supina Schur (Hadač 1944), a name now synonymized with the C European F. airoides Lam. Hadač was not alone in this use of name; the name F. supina has been applied also to other plants in the Arctic, in lack of a functional taxonomy of the arctic fescues. Rønning (1961) assigned Hadač F. supina to his extended concept of F. brachyphylla, which at that time included F. edlundiae.

Fjellheim et al. (2001) found possible hybrid plants intermediate in RAPD markers and morphology in the large, mixed population of F. brachyphylla and F. edlundiae on disturbed ground by the airport in Longyearbyen (Hotellneset). As the parent species are well proved to be, respectively, hexaploid and tetraploid, these assumed hybrid plants are probably pentaploid (2n = 35) and sterile.

At present, the Festuca species of this complex are fairly well resolved in Svalbard: the widespread species is F. edlundiae as described by Aiken et al. (1995), whereas the otherwise major arctic species, F. brachyphylla, is quite restricted and the high arctic F. hyperborea (mapped as common by Rønning 1972) is very rare, here as elsewhere in the Eurasian Arctic. For maps and much additional information, see Fjellheim et al. (2001) and Guldahl et al. (2001).

Aiken, S.G., Consaul, L.L. & Lefkovitch, L.P. 1995. Festuca edlundiae (Poaceae), a high arctic, new species compared enzymatically and morphologically with similar Festuca species. – Systematic Botany 20: 374–392.

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.

Chernov, E.G. 1953. Festuca L. (s. str.). – In: Gorodkov, B.N. (ed.), Flora Murmanskoi Oblasti I: 222–230.

Fjellheim, S. 1999. RAPD DNA and morphological variation in seminiferous taxa of the Festuca brachyphylla complex (Poaceae) in Svalbard. – Cand. scient. thesis, Univ. Oslo, Oslo.

Fjellheim, S., Elven, R. & Brochmann, C. 2001. Molecules and morphology in concert. II. The Festuca brachyphylla complex (Poaceae) in Svalbard. – American Journal of Botany 88: 869–882.

Guldahl, A.S. 1999. The Festuca brachyphylla complex in Svalbard: enzymatic, chromosomal, and ecological variation. – Cand. scient. thesis, Univ. Oslo, Oslo.

Guldahl, A.S., Borgen, L. & Nordal, I. 2001. Variation in the Festuca brachyphylla (Poaceae) complex in Svalbard, elucidated by chromosome numbers and isozymes. – Botanical Journal of the Linnaean Society 137: 107–126.

Hadač, E. 1944. Die Gefässpflanzen des "Sassengebietes" Vestspitsbergen. – Skrifter om Svalbard og Ishavet 87. 72 pp. + XIV Tafel.

Rønning, O.I. 1961. Some new contributions to the flora of Svalbard. – Norsk Polarinstutts Skrifter 124. 20 pp.

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