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GROWTH FORM

Solitary graminoid herb growing in tussocks with intravaginal branching only (all branches appear inside the leaf sheaths, no runners or stolons); however, the large and sometimes loose tussocks may merge into extensive mats. Culms 5−15(20) cm, erect, glabrous in lower parts, rather densely pubescent with short, stiff hairs pointing upwards on upper parts. Base of shoots surrounded by straw-coloured sheaths of previous years' leaves. Usually no prophylls (scaly leaves without a developed blade at base of leafy and reproductive shoots) or sometimes one.

LEAF

Leaves bright green, filiform, narrowly convolute, with continuous sclerenchyma (strengthening tissue) and therefore no ribs, with short, stiff hairs throughout. Basal leaves 5−8 cm long, shorter than culms, 0.2−0.3 mm broad. Leaf sheaths open. Uppermost culm leaf (the 'flag leaf') blade filiform, 1.5−2.5(3) cm, attached well below the middle of the culm. Ligula very short (0.1−0.3 mm), truncate.

INFLORESCENCE AND FLOWER

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’ are essential in the opening of the flower at anthesis (possibly transformed perianth leaves or transformed stamens), usually 3 stamens, and a gynoecium of 2 fused carpels with 2 feathery stigmas and one seed.

Inflorescence an elongate, open, greyish-violet or greyish-green panicle, 1.5−3 cm long, less than 1/3 of culm length. Panicle branches short, 3−4(5) mm, at 4−7 nodes with 1−2 branches at the lower nodes, 1 at the upper ones. Branches densely scabrous or stiff pubescent, each with 1−3 spikelets. Spikelets 6−7 × 2.5−3.5 mm (awns included), with 4−6 flowers. Bracts (glumes and lemmas) with rounded backs. Glumes 2−3 mm, the lower a little shorter than the upper, acute or abruptly narrowed into an acute to apiculate apex, with 1−3 indistinct veins, glabrous and shiny in the proximal part, pubescent and dull in the distal part, violet with a narrow, white or yellowish scarious margin. Lemmas (excluding awn) 3.5−5 mm, with several indistinct or distinct veins, dull, scabrous or stiff pubescent especially in the distal part, with an awn 1.5−2 mm. Paleas scabrous on veins, pubescent between veins. Anthers well developed, 1.8−2.2 mm.

FRUIT

Fruit an achene (with one seed).

REPRODUCTION

Sexual reproduction by seeds; no vegetative reproduction. Wind pollinated. Seed production is not studied. However, spikelets of previous years are observed partly with shed flowers (suggesting mature and dispersed fruits), and partly with retained ones (suggesting problems with seed-set) (R. Elven observ. 2010).

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

COMPARISON

The fescues of Svalbard belong to several groups, all within the major section Festuca. 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).

The two best diagnostic characters of Festuca ovina compared with the F. brachyphylla group are the anther length − ca. 2 mm in F. ovina and ca. 1 mm in the F. brachyphylla group − and the sclerenchyma of the leaves – continuous in F. ovina and discontinuous in the F. brachyphylla group. The anther character can be observed rather easily when flowering plants are studied. The sclerenchyma character requires a microscope to see the leaf cross-sections but the leaf surface usually gives a good suggestion; leaves with a continuous sheath of sclerenchyma are terete (round in cross-section), those with discontinuous sclerenchyma are ribbed (angular in cross-section). This difference is particularly distinct on dry leaves, e.g., leaves from previous year at base of plant. Comparing Svalbard plants, the issue is easier. Festuca ovina has hairy leaves whereas both the F. brachyphylla group and F. baffinensis have glabrous leaves. F. ovina also has short, stiff hairs on the upper part of the culm, absent in the F. brachyphylla group.

HABITAT

Only observed in the arctic steppe regions in Wijdefjorden. The largest concentrations in scree with some influence by bird cliffs, but also occurring in dry heaths and meadow depressions. The dry conditions in the steppe areas lead to wind (aeolic) transport and deposition of silt and sand from the glacial rivers everywhere. Hence, the substrate which receive abundant mineral nutrients supports a basiphilous vegetation.

DISTRIBUTION

Strongly thermophilous. Festuca ovina was found in 2010 and 2015 in several sites in and between the two valleys Ringhorndalen and Flatøyrdalen on the east side of Wijdefjorden in Ny-Friesland, N Spitsbergen: Flatøyrdalen (at least two separate stands), Heimdalshallet (several stands in scree and meadows), and Ringhorndalen (large occurrences in scree), all within an area of 4 × 5 km. All stands are within the middle arctic tundra zone and the clearly continental section, in the largest area of arctic steppe in Svalbard (see Elvebakk & Nilsen 2002). The species may have been noted already by Arve Elvebakk and Lennart Nilsen in 2002 as they noted a Festuca they could not identify from the same area.

The species is otherwise a temperate−alpine plant of Europe and W Siberia. It reaches far north on the mainland in Norway, the Polar Ural in European Russia, and Taimyr in Siberia (Hultén & Fries 1986; Tolmachev et al. 1995; Malyschev & Peschkova 2001), but not the arctic islands except for Svalbard (i.e., not Russian Novaya Zemlya). The distances from the Svalbard occurrences to the nearest ones known elsewhere are rather long, 900−1000 km to N Norway and ca. 2600 km to the Polar Ural. The species is absent from the western Arctic (Greenland, North America) except for some introductions.

COMMENTS

The isolated occurrences of Festuca ovina in N Spitsbergen are enigmatic but not more so than the occurrences in the same valleys, along the east side of Wijdefjorden, of the only known Svalbard localities for Calamagrostis purpurascens (Elvebakk & Nilsen 2002), Pinguicula alpina (Eidesen et al. 2013), and Erigeron uniflorus (Eidesen et al. 2016) and of numerous occurrences of other very rare species in Svalbard, among others Arctagrostis latifolia, Campanula uniflora, Carex krausei, Comastoma tenellum, Erigeron eriocephalum, and Puccinellia svalbardensis (for this species, see Elvebakk & Nilsen 2011). The presence of so many regionally unique or rare and strongly isolated species in the arctic steppes by Wijdefjorden suggest a common history rather than accidental long distance dispersal of all these species to just this very small area.

LITERATURE

Eidesen, P.B., Arnesen, G., Elven, R., Søli, G. 2016 Kartlegging av Ringhorndalen, Wijdefjorden: En uutforsket arktisk oase.

Eidesen, P.B., Strømmen, K. & Vader, A. 2013. Fjelltettegras Pinguicula alpina funnet ny for Svalbard i Ringhorndalen, Wijdefjorden, en uutforsket arktisk oase. − Blyttia 71: 209−213.

Elvebakk, A. & Nilsen, L. 2002. Indre Wijdefjorden med sidefjordar: eit botanisk unikt steppeområde. − Rapport til Sysselmannen på Svalbard utgitt av Universitetet i Tromsø. 66 pp.

Elvebakk, A. & Nilsen, L. 2011. Svalbardsaltgras Puccinellia svalbardensis − endemisk for Svalbard, men vanleg i steppeområdet ved Wijdefjorden. − Blyttia 69: 173−183.

Hultén, E. & Fries, M. 1986. Atlas of North European vascular plants north of the Tropic of Cancer. I–III. – Cramer, Vaduz.

Malyschev, L.I. & Peschkova, G.A. (eds.) 2001. Flora of Siberia. 2. Poaceae (Gramineae). – Science Publishers, Inc., Enfield & Plymouth.

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

PHOTOS FESTUCA OVINA

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Observations in svalbard

__Herbarium specimen __Observation

ALL SPECIES OF THE GENUS Festuca