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Solitary graminoid herb growing in dense or loose, often large tussocks with all branching inside leaf sheaths (intravaginal, i.e., no runners). Culms to 10–25(30) cm, erect, smooth and glabrous. Base of shoots densely surrounded by pale, straw-coloured sheaths of marcescent leaves. Prophylls (scaly leaves without developed blade at base of shoots) 1–2, hyaline.
Leaves filiform (involute), rarely flat, tapering towards apex, with 3–5 veins, distinct on the lower surface, raised as pale ribs on the upper surface, smooth on both surfaces. Basal leaves of aerial shoots 5–15(20) cm long, shorter than culms, 0.4–0.8(1.0) mm broad. Culm leaves 2–3, 3–10(12) cm long, decreasing significantly in length upwards on culm, 0.8–1 mm broad, involute, flag leaf blade attached more or less at middle of culm or above. Ligula long, 1.5–6.5 mm, acute, entire.
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’ 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 panicle 4–10(12) cm long, occupying 1/3–1/4 of culm length, with ascending to spreading branches. Panicle with 5–9 well separated nodes with 3–5 branches at each of the lower nodes. Branches 20–40(50) mm, smooth, each with 4–6(7) spikelets. Spikelets 3–5 × 1–1.5 mm, with 2(3) flowers, the third, if present, usually reduced and non-functional. Bracts (glumes and lemmas) with rounded backs. Glumes narrowly lanceolate, acuminate, lower glume 2.5–3.5 mm, upper glume 3.5–4.5 mm, as long as spikelet, with a distinct mid vein (often contrasting dark) and 2 more or less distinct lateral veins, mid vein smooth, glume surface shiny, either white and pale golden yellow hyaline throughout or with violet mid part not reaching more than 1/2 way up the glume. Lemmas 2.5–4 mm, lanceolate with deeply lacerate apex, with (3)5–7 little visible veins, shiny, glabrous, with awn 0.7–2.2 mm attached at the lower half of the mid vein, inserted or slightly exerted from the spikelet. Paleas strongly reduced or absent. Stamens 3; anthers 0.7–2 mm, well-developed or sometimes shrivelled.
Fruit an achene (with one seed).
Sexual seed reproduction; very local vegetative reproduction by fragmentation of diffuse tussocks, especially in dense, wet moss mats (R. Elven observ.). Wind pollination. Seeds are probably produced regularly in Svalbard although no ripe seeds were found in 2008 (Alsos et al. 2013).
Fruits are dispersed inside florets. There is no special adaptation to fruit dispersal but the awn may adhere to animals.
The character most clearly distinguishing young plants of Deschampsia sukatschewii from those of D. alpina and D. cespitosa is the number of veins in the leaves, 3–5 in D. sukatschewii, 5–10 in the two others. Deschampsia sukatschewii also has filiform, significantly narrower leaves than the two others.
Occurring in flat or gently sloping, shallow marshes or wetlands, usually permanently wet but not permanently inundated. Only reported from quite fine-grained, calcareous substrates.
In Svalbard, Deschampsia sukatschewii is only known from Spitsbergen where it is confined to the middle and northern arctic tundra zones and the transitional to clearly continental sections. It is common in the calcareous districts at the inner Isfjorden (Sabine, Bünsow and Dickson Lands) and Wijdefjorden (Dickson and Andrée Lands, Ny-Friesland), has more sparse occurrence at the outer Bellsund (Wedel Jarlsberg, Nathorst and Nordenskiöld Lands), otherwise only with very sparse occurrence at the outer Isfjorden (in Nordenskiöld Land west to Isfjord Radio) and with a single record from Breinesflya in Sørkapp Land.
Elsewhere this is a high arctic, circumpolar species, the most widespread Deschampsia in the northernmost lands in Europe, Asia, North America, and Greenland.
Looking at early works on the flora of Svalbard (before 1996, e.g., Rønning 1964, 1972, 1979), you will find this species uniformly denoted as Deschampsia brevifolia R.Br. The reason for using this name is rather difficult to understand today. Deschampsia brevifolia is a distinct species characterized by an unusually compact panicle (wide open in D. sukatschewii), much larger spikelets, and unusually short but very stiff and stout leaves (long, slender and soft in D. sukatschewii), and very dense tussocks on fairly dry ground (loose tussocks on wet ground in D. sukatschewii). The mistake is even more surprising as also D. sukatschewii is frequent in N Greenland and Canada, the areas Svalbard botanists looked to for finding a name for the Svalbard plant.
Another name commonly used for this plant in previous times, sometimes also in Svalbard, is D. pumila (Griseb.) Ostenf. 1923. However, this name is predated by D. pumila (Steven ex Westb.) Fomin & Woronow 1907, belonging to a plant from the Caucasus. Ostenfeld's species name was therefore a later homonym (same name, but different plant) and had to be replaced.
Deschampsia sukatschewii is reported as diploid (2n = 26), triploid (2n = 39) and tetraploid (2n = 52), and also with several counts of numbers between these levels. This may explain the frequent occurrence of plants with aborting anthers. However, no asexual seed-set (agamospermy) is assumed.
The choice of the name D. sukatschewii ssp. borealis for the Svalbard plant may be a provisional solution. Tzvelev in Elven et al. (2011) argued for D. sukatschewii as a polymorphic species with three major subspecies: the Siberian ssp. sukatschewii, the amphi-Beringian ssp. orientalis (Hultén) Tzvelev, and the circumpolar ssp. borealis. Other authors have argued against a subspecific split of the species (Barkworth 2007). There are yet no convincing molecular studies of this group, even if Deschampsia has been given much attention in the last decades (see Elven et al. 2011 with numerous references).
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.
Barkworth, M.E. 2007. Deschampsia P. Beauv. – In: Flora of North America Editorial Committee (eds.), Flora of North America north of Mexico. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1: 624–633.
Elven, R., Murray, D.F., Razzhivin, V. & Yurtsev, B.A. (eds.) 2011. Annotated Checklist of the Panarctic Flora (PAF).
Rønning, O.I. 1964. Svalbards flora. – Norsk Polarinstitutt, Oslo.
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.