Solitary graminoid herb growing in small, dense tussocks with intravaginal branching (e.g., with no runners or stolons). Culms 2–5 cm, erect, glabrous and smooth. Base of shoots surrounded by yellowish white sheaths of leaves from previous years. Usually no prophylls (scaly leaves without a developed blade at base of leafy and reproductive shoots) or sometimes one.

Leaves green, filiform, narrowly convolute with ribs due to sclerenchyma (strings of discontinuous strengthening tissue), smooth or with a few spinules in margins and along veins apically. Basal leaves 1–2 cm long, 1/2–2/3 the length of the culm, 0.3–0.5 mm broad (when convolute), very rarely flat. Leaf sheaths open. Uppermost culm leaf (the 'flag leaf') blade extremely small, 0–4 mm long, spoon-shaped, attached in the lower 1/3 of the culm. Ligula very short (less than 1 mm), truncate.

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 a very short, narrow, several-sided, blackish purple panicle 0.6–1.0 cm long, occupying less than 1/3 of culm length. Panicle branches very short (1–2 mm), with few, short spinules, each branch usually with a single spikelet; the entire inflorescence often with less than 5 spikelets. Spikelets 4.5–6.5 × 1.5–2.0 mm (awns included), with 3–4 flowers. Bracts (glumes and lemmas) with rounded backs. Glumes 2.0–3.0 mm, the lower one shorter than the upper one, acute to acuminate, the upper or both glumes often with slender fringes or hairs in apex and along margins, with 1–3 indistinct veins, glabrous and shiny. Lemmas (awn not included) 2.8–4.0 mm, with several more or less distinct veins, scabrous, especially in distal parts, with a very scabrous awn 1.0–2.0 mm. Paleas scabrous both on and between veins. Anthers well developed, 0.4–1.1 mm.

Fruit an achene (with one seed).

Sexual reproduction by seeds; no vegetative reproduction. Wind pollination. Seed production probably efficient as the plant, although very local, occurs with large populations with hundreds or perhaps thousands of individuals over several km² (R. Elven observ.).

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.

The extremely short flag leaf blade is the best diagnostic character for recognition of F. hyperborea in Svalbard. However, care should be taken when investigating this character because the leaf sheath often is loose from the culm (due to the open leaf sheaths is this group of Festuca), making the flag leaf blade appear much longer than it is. One should look for the ligula, located at the transition from sheath to blade. The general appearance of F. hyperborea in the field is like an extremely small F. brachyphylla.

Festuca hyperborea is known from alpine or polar desert sites only with open, frost-patterned ground with much fine material, or very rarely along brook and river margins downstream from such sites. The only stands observed in recent times are located on the polygon soils of the Coloradofjella mountains in Sassendalen (Sabine Land), where the species is fairly common in open frost-scattered vegetation with, e.g., Papaver and Cerastium regelii, and on two river gravel bars in Adventdalen (Nordenskiöld Land) where a very few plants have been found, both localities in interior parts of Spitsbergen. In Svalbard, this species is obviously a weak competitor, however, efficiently colonizing new patches as they appear due to frost disturbance.

Cryophilous. Festuca hyperborea is confirmed only from 5 localities or small locality groups: on Spitsbergen in Adventdalen (Nordenskiöld Land) where only a few plants have been found on river banks (probably secondary from mountain populations somewhere in the vicinity), in Sassendalen (Sabine Land) where abundant primary populations are known on Coloradofjella, and at the head of Lomfjorden (Ny-Friesland) where it was found once in 1931 (Scholander 1934), on Nordaustlandet from two finds at Wahlenbergfjorden (Gustav Adolf Land; one unspecified "Wahlenbergfjorden" in 1957, one at Kløverbladbukta in 1965), and on the northern tip of Barentsøya (see map in Fjellheim et al. 2001).

The cryophilous pattern is repeated elsewhere; Festuca hyperborea is barely found south of the northern arctic tundra zone anywhere in the world. Its range is circumpolar except that it is missing from the large stretches in Alaska, the Russian Far East, Siberia, and Europe where no land reaches the northernmost zones. The closest proven sites to the east of Svalbard are found on the Taimyr Peninsula in Siberia (see Elven et al. 2011) with a few records from the offshore Severnaya Zemlya and Novosiberian Islands. Westwards, it is frequent throughout N Greenland and the Canadian Arctic Archipelago but not farther west in North America. The connection of the Svalbard plants seems to be to the west.

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 discovery of Festuca hyperborea, both as a species in its own right and as a species of Svalbard, are instructive examples of the steps in elucidation of arctic biodiversity. The species was first discovered by cytological means when Holmen (1952) found tetraploid plants in N Greenland, within the range of the known hexaploid F. brachyphylla. Holmen informally suggested the plant as a new species, F. ‘hyperborea’ but did not describe the species in a formally correct way, a procedure left for Frederiksen (1977). However, Holmen's notes on the new species were enough for Rønning (1961, 1972) to try to separate and map the abundant Svalbard materials on the two species (F. brachyphylla for all tall-grown plants and F. hyperborea for all short-grown plants). This division is reflected in his treatment for the Flora of Svalbard (Rønning 1979). The vast majority of collections of the F. brachyphylla group from Svalbard thereafter were labelled based on the names and characters proposed by Rønning. No-one was very comfortable with this treatment. The current solution was reached when Aiken et al. (1995) showed that rather than two, there were three distinctive species involved, and that ca. 90 % of the Svalbard material mapped by Rønning (1972) as F. brachyphylla and F. hyperborea belonged to the third species: F. edlundiae. After this time, F. hyperborea has been accepted as a very rare, high arctic plant in Svalbard (Elven & Elvebakk 1996; Lid & Lid 2005; Elven et al. 2011, 2022) and has been studied further by several means (Fjellheim 1999; Fjellheim et al. 2011; Guldahl 1999; Guldahl et al. 2001). In Russia, Alexeev (e.g., as late as in Tolmachev et al. 1995) followed the same approach as Rønning, and the material in Russian herbaria has, as far as we know, not yet been revised according to the new knowledge. This makes it difficult to say which species are present in the Russian areas nearest to Svalbard (Franz Joseph Land, Novaya Zemlya, northern mainland European Russia.

The rarity of F. hyperborea in Svalbard is surprising. These small fescues have been seen as an interesting group as none of them are exactly common. Hence, they have been collected regularly by professionals and amateurs alike, more so than many other plants. The abundant material must be considered a representative sample, and also as a fairly random one as no one has known which species they actually collected until very recently. The very low number of collections belonging to F. hyperborea is therefore a strong indication that the species really is rare in Svalbard.

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.

Elven, R., Bjorå, C.S., Fremstad, E., Hegre, H. & Solstad, H. 2022. Norsk flora. 8. Ed. – Det Norske Samlaget, Oslo.

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/

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.

Frederiksen, S. 1977. The Festuca brachyphylla group in Greenland. – Botaniska Notiser 130: 269–277.

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.

Holmen, K. 1952. Cytological studies in the flora of Peary Land, north Greenland. – Meddelelser om Grønland 128(5). 40 pp.

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

Rønning, O.I. 1961. Some new contributions to the flora of Svalbard. – Norsk Polarinstitutts 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.

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

Scholander, P.F. 1934. Vascular plants from northern Svalbard. – Skrifter om Svalbard og Ishavet 62. 152 pp.

Tolmachev, A.I., Packer, J.G. & Griffiths, G.C.D. (eds.) 1995. Flora of the Russian Arctic. I. Lycopodiaceae–Gramineae. – Univ. Alberta Press, Edmonton.