Solitary graminoid herb growing in dense tussocks with all branching inside leaf sheaths (intravaginal, i.e., no runners or stolons). Culms 18−25 cm, erect, smooth in their lower part, densely scabrous beneath the panicle with short, stiff hairs. Base of shoots densely surrounded by shiny, pale straw-coloured, withered leaf sheaths. Usually no prophylls (scaly leaves without a developed blade at base of leafy and reproductive shoots) or sometimes one.

Leaves filiform, narrowly convolute, with discontinuous strings of sclerenchyma (strengthening tissue) making leaves distinctly angled (with ribs) in cross-section, with sparse, stiff hairs on ribs. Basal leaves 5−8 cm long, less than 1/2 length of culms, narrow, 0.4−0.6 mm. Leaf sheaths open for much of their length. Culm leaves filiform; uppermost one (the 'flag leaf') with 1.5−2 cm blade, attached at the middle of culm or below. Ligula very short (less than 0.5 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).

Inflorescence an elongate, fairly dense, one-sided panicle, 3−4 cm long, occupying less than 1/3 of culm length. Panicle branches short (3−4 mm), 1−2 at each node, pubescent with dense, short, stiff hairs or scabrous, each branch normally with 1−3 spikelets. The spikelets probably with 3−5 flowers initially, but except for the lowermost 1−2 they are early transformed into a bulbil. Bracts (glumes and lemmas) with rounded backs. Glumes unequal, the lower 3−4 mm, narrowly lanceolate, the upper 4−5 mm, lanceolate, both acute but without awn, with 1(3) indistinct veins, shiny, glabrous in lower (proximal) part, spinulosely hairy in upper (distal) part, fringed by short, stiff hairs in upper part. Lemmas (when not transformed) 4−6 mm, lanceolate, acute but without awn, with ca. 3 distinct veins, densely pilose. Stamens not observed.

No seed-set observed in Svalbard plants. Most flowers in the spikelet replaced by a single, leafy bulbil (vivipary).

Only asexual reproduction by bulbils. For more information on bulbil reproduction and dispersal, see Festuca viviparoidea.

Grasses that regularly reproduce by bulbils (vivipary) in Svalbard belong to three genera: Deschampsia, Festuca and Poa. All viviparous Deschampsia and Festuca are tussock-forming with intravaginal branching only, whereas all viviparous grasses with extravaginal branching and rhizome systems (mat-forming) belong to Poa. Deschampsia alpina is distinguished from Festuca and Poa by much stouter leaves with raised veins on the upper surface (often hidden because the leaves are convolute), shiny hyaline glumes and lemmas, and spikelets with only two flowers (the two other genera have spikelets with several flowers). Viviparous Festuca and Poa are easily kept apart by the former having filiform leaves and acute glumes with rounded back, the latter having flat or folded leaves and broadly ovate glumes with keel.

The Festuca vivipara group (F. frederikseniae, F. vivipara, F. viviparoidea) differs from the other tussock-forming species of Festuca in Svalbard (F. baffinensis, the F. brachyphylla group, F. ovina) in being viviparous with panicles with bulbils developed instead of fruits. The elongation and transformation of the lemmas into the leaves of the bulbils is observable rather early in the flowering season. Where developed panicles are not available, the species may be more difficult to distinguish but the following characters can be used. The F. vivipara group has glabrous leaves vs. hairy leaves in F. ovina (in Svalbard). The glumes and lemmas of the F. vivipara group are narrowly lanceolate, almost linear, and the lemmas are without awns vs. the more broadly lanceolate glumes and lemmas and the awned lemmas in F. baffinensis, the F. brachyphylla group, and also F. ovina.

The differences between the three species of the F. vivipara group are more subtle but their distributions in Svalbard are rather different. Festuca vivipara is the only species of this group on Bjørnøya, F. frederikseniae is at present only known from a single locality at Dicksonfjorden on Spitsbergen, whereas all other plants in Svalbard currently are assigned to F. viviparioidea. There are some morphological differences considered to be taxonomically important, even if they are not always readily observed. Festuca vivipara (and F. ovina) has a continuous sheet of schlerenchyma in the leaves, making leaves terete in cross-section (one needs a lens with strong magnification or a microscope). Festuca frederikseniae (in the Svalbard meaning) and F. viviparoidea (and F. baffinensis and the F. brachyphylla group) have discontinuous sclerenchyma resulting in slight to distinct ribs on the surface of the leaves, making them more or less angular in cross-section. This angular cross-section is also found in F. rubra and in possible hybrids between that species and F. ovina. The most easily observed difference between the three species of the F. vivipara group is found in the lemmas. The lemmas of F. vivipara are normally greyish green or pale violet and pubescent with short, stiff hairs; those of F. viviparoidea are greyish violet or purple and smooth and glabrous, at least in their lower parts; and those of F. frederikseniae are greyish violet and densely pilose.

Little is known about the habitat. The area where it was found is among the driest in Svalbard with much open ground and mineral nutrients due to wind-blown silt. The bedrock is Devonian claystone and sandstone, producing very fine-grained soils with a basic soil reaction (pH).

Festuca frederikseniae has been collected once, in Dickson Land near Dicksonfjorden, a tributary fjord on the north side of Isfjorden: in "Hugins dal 5 km frå sjøen, under Triplex" [in Hugins valley, 5 km from the sea, under the mountain Triplex, now Triungen between Triungsdalen and Kulmdalen] on 12. Aug. 1924, leg. Ove Arbo Høeg. As far as we know, since then this site (and even valley) has not been visited by any botanist capable of noting this plant. The entire material known to us consists of two herbarium sheets in Oslo (O).

The general range is western amphi-Atlantic, restricted to E Canada, Greenland and the locality in Svalbard (if it has been correctly identified, see Comments).

For general comments to the Festuca vivipara group, see F. viviparoidea. Festuca frederikseniae is nomenclaturally a ‘new name’ (nomen novum) for what before was called F. vivipara ssp. hirsuta (Schol.) Fred., again based on F. vivipara var. hirsuta Schol. Scholander (1933) described his new variety due to the outstanding pubescence on the lemmas and some other characters. The original material, on which he based the description, was his own collections together with J. Devold from SE Greenland and the Hugindalen collection from Svalbard, annotated by him as "Festuca vivipara (L.) Sm. var. hirsuta (Lge.) m[ihi]. Det. Schol. 1933". The "m[ihi]" means that this is part of the original material (syntypes) that could be chosen as a lectotype to confirm the name's connection to a certain plant. However, Frederiksen (1981) chose an older specimen from Frederiksdal (Narsarmijit) in southernmost Greenland as the lectotype. She mapped the range of her ssp. hirsuta to include only areas in Greenland and Canada (Frederiksen 1981: 288). She thereby seems to have excluded or forgotten this Svalbard specimen and confirmation by Scholander, even if there is a pencil note in Signe Frederiksen’s handwriting, "v. hirsuta", on the labels on both sheets.

Why do we have doubts whether the Svalbard plant belongs to F. frederikseniae? The reason is that there is one essential difference between F. frederikseniae in the type meaning from Greenland and the Svalbard plant: the leaf anatomy. As described by Frederiksen (1981, and as she chose the type, she is the undisputable authority in this matter). F. frederikseniae in the type meaning has a thin, continuous sheet of sclerenchyma (Frederiksen 1981: 285) and terete leaves with no ribs; the Svalbard plant has a thick, but discontinuous sclerenchyma and unusually distinct ribs. This character is considered of crucial importance in drawing limits between species and species groups among the filiform-leaved Festucas. Therefore, the Svalbard plant can scarcely belong to F. frederikseniae as considered by Frederiksen.

But what is it? We do not know. There are two possibilities: either a yet unrecognized species; or a strange hybrid, and if so, between Festuca viviparoidea (that probably produces a few pollen grains now and then) and F. rubra ssp. richardsonii. Festuca rubra could be responsible for the pilose lemmas and could also contribute to the ribbed leaves. However, both these characters are present also among other species of the F. vivipara group and do not have to come from F. rubra. We find both explanations improbable but especially the latter, hybrid explanation, as there are no signs in Svalbard F. frederikseniae of any of the specific characters found in F. rubra and its hybrids: extravaginal branching with creeping rhizomes, strongly ribbed culms, two or more prophylls, lack of sheath cylinders at shoot bases, closed leaf sheaths, auricles, etc. Hence, there are no features pointing unambiguously in the direction of F. rubra.

Devold, J. & Scholander, P.F. 1933. Flowering plants and ferns of Southeast Greenland. − Skrifter om Svalbard og Ishavet 56. 215 pp.

Frederiksen, S. 1981. Festuca vivipara (Poaceae) in the North Atlantic area. – Nordic Journal of Botany 1: 277–292.