Solitary graminoid herb growing in small, dense or loose tussocks with all branching inside leaf sheaths (intravaginal). Roots not curled. Basal sheaths pale straw-coloured, with strong, pale veins, in dense or loose cylinders. Aerial shoots with 2–3 prophylls (basal, reduced leaves without or with only a short blade). Culms 5–15 cm, prostrate or ascending, smooth and glabrous, with 1–3 leaves.
Leaves 3–7 cm long, less than half as long as culms in well developed plants, keeled, mostly folded, with apex like the prow of a boat, with veins on the upper surface broad and distinctly raised, on the lower surface narrow and less distinctly raised, smooth except for being slightly scabrous on midvein and margins in the apex, glabrous, usually tinged violet or pale purple. Ligula 1.5–2 mm, more or less truncate, strongly lacerate.
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, up to 7 × 5 cm and usually occupying 1/2–1/3 of culm length, the entire panicle violet with bloom (wax) on culm and branches. Panicle with 5–7 nodes with 1–2(3) branches at each of the lower nodes. Branches spreading or retrorse, 10–25(30) mm, sparsely scabrous, each with 3–6(8) spikelets in their distal half. Spikelets 3–4 × 1.8–2.1 mm, with 3–4 flowers. Bracts (glumes and lemmas) with rounded backs. Glumes unequal, both much shorter than the lower lemmas, smooth and glabrous, flimsy. Lower glume 0.8–1.2 × 0.5–0.7 mm, ovate, obtuse with a lacerate apex, with 1 vein, violet and usually without hyaline margin; upper glume 1.2–1.7 × 0.8–1.0 mm, ovate or oblong, rounded at apex, strongly lacerate, with 1–3 veins, violet with a narrow white hyaline margin and apex. Lemmas 1.8–2.2 × 1.0–1.4 mm, oblong, rounded, strongly lacerate, with very indistinct veins (ca. 5), smooth, with few hairs at base (no hairs up on veins), violet with a more or less narrow yellowish and white hyaline margin. Paleas as long as lemmas, with veins smooth and glabrous in their proximal ca. 2/3, scabrous in their distal ca. 1/3. Anthers 0.4–0.5 mm.
Fruit an achene (with one seed).
Sexual reproduction by seeds; no vegetative reproduction. Wind pollinated. Seed set is regular in the populations at Pyramiden, Bockfjorden, and Wijdefjorden (see below), possibly more problematic at Kongsfjorden.
There are no special adaptations to dispersal, main dispersal (fruits inside florets) probably mainly by wind, occasionally perhaps by birds.
The species of Puccinellia can be mistaken for Poa but differ in having no keel on glumes or lemmas but rather an evenly rounded back. They also differ in lemmas broad nearly to the apex, often truncate, rounded or subacute with apex uneven, lacerate or fringed, whereas all Poa have lemmas tapering gradually towards a usually acute apex and usually entire in the margin (however, the lemmas of Poa abbreviata, P. glauca and P. hartzii may have lacerate apices).
The genus Puccinellia is notoriously difficult and with numerous species in the Arctic, many of them endemic (restricted) to the arctic regions. They are difficult also in Svalbard. We here recognize 5 species but there may be more (especially in the affinity of P. angustata).
Puccinellia phryganodes differs from all the others in being stoloniferous and asexual with aborting flowers (look for shrivelled anthers) and little flowering; all the others are tussocky, sexual and always abundantly flowering. For the unmistakeable stolons of P. phryganodes, see that species.
Puccinellia angustata and P. vahliana both have paleas with intertwined hairs on the proximal parts of the veins (keels), whereas P. coarctata and P. svalbardensis have no intertwined hairs on palea keels. Puccinellia vahliana differs most distinctly from P. angustata in the glumes. In P. vahliana they are mostly subequal, the longest about the same length as the lower lemmas, and firm; in P. angustata they are unequal, both much shorter than the lower lemmas, and flimsy.
Puccinellia svalbardensis differs from (arctic) P. coarctata most distinctly in the shape of the panicle. The panicle of P. svalbardensis is very open with very slender, spreading to patent or even retrorse, long branches; that of P. coarctata is more contracted with stouter, erect or erectopatent branches. The keels (veins) of the paleas in P. svalbardensis are smooth, those of P. coarctata scabrous at least in their distal parts. In addition, the lemmas of P. svalbardensis are lacerate, whereas those of P. coarctata are distinctly ciliolate (with one-celled teeth). Mistaking these two species is, however, impossible in practice in Svalbard as P. coarctata is a seashore species restricted to Bjørnøya, whereas P. svalbardensis mainly is an arctic steppe species and restricted to northern parts of Spitsbergen.
The site types are very different in the four areas where this species is known (see Distribution). On the Lovén Islands the species seems to grow in meadow and heath vegetation heavily grazed and manured by geese. At Bockfjorden it grows on occasionally very dry gravel plains close to the warm springs, with a heat source in the soil, possibly occasionally submerged (at least in the past) by spring water, and with a basic soil reaction (pH). At Wijdefjorden it is a regular constituent of the arctic steppe vegetation on open silt and gravel plains and in open patches in heath, always with a moderately to highly basic soil reaction (see Elvebakk & Nilsen 2011). In the Pyramiden area it occurs mainly on disturbed ground, partly ruderal, close to the settlement and perhaps on the river valley plain, always with a basic soil reaction.
Puccinellia svalbardensis is only known from the middle arctic tundra zone and the clearly and weakly continental sections. This species has its entire known range in the world in four small areas on Svalbard: on the Lovén Islands in Kongsfjorden (Haakon VII Land), very close to the warm springs Trollkjeldane at Bockfjorden (Haakon VII Land), along the eastern side of inner Wijdefjorden in the main area of arctic steppe in Svalbard (Ny-Friesland), and at Pyramiden and in Mimerdalen at Billefjorden in the Isfjorden area (Dickson Land). The finds in the last-mentioned area were made by D. Thannheiser in 1996 but recognized as belonging to this species as late as in 2014 and confirmed by new finds in 2014 when it was seen in large amounts in the now abandoned Russian mining settlement.
This Svalbard endemic species is enigmatic. Before its description as the new species Puccinellia svalbardensis by Rønning (1963) this Svalbard plant was assigned to P. tenella (Lange) Holmb. Hughes & Halliday (1980) did not accept P. svalbardensis but commented on it in connection with P. tenella from which it differs markedly morphologically and also in being hexaploid rather than diploid. Puccinellia tenella belongs to a morphologically well characterized sect. Tenellae, whereas P. svalbardensis does not share any of the characters diagnostic for sect. Tenellae and is rather a typical member of sect. Puccinellia.
The species was first described from a single group of small bird-manured islands, the Lovén Islands in Kongsfjorden, now so heavily grazed by geese that very few flowering shoots (if any) have been seen in the latter years. The species has accordingly been considered acutely threatened in Norway (and globally). Reports from two ecologically similar but quite distant island groups in Svalbard (Lernerøyane in Liefdefjorden and Gyllenskiöldholmene in Wijdefjorden) have not been confirmed. However, Elvebakk & Nilsen (2002) reported it to be frequent in the arctic steppe areas at inner Wijdefjorden, further described by Elvebakk & Nilsen (2011) and confirmed by I.G. Alsos, G. Arnesen P.B. Eidesen, A.K. Brysting and R. Elven in 2010 and later. We have also transferred the record of P. palibinii T.J.Sørensen from the warm springs at Bockfjorden (Elvebakk et al. 1994) to P. svalbardensis, and there are recent collections (1996, 2014) from at least three sites close to and within the settlement of Pyramiden at Billefjorden. The species has probably been overlooked and is not nearly as rare and threatened as previously assumed.
Even if we have a much better understanding of P. svalbardensis now than when it was a very restricted plant known only from the Lovén Islands, it is still a mystery. It is now one of the five regular Puccinellia species in Svalbard, as different from the others as they are from each other, and still with no obvious parallel in the eastern or western Arctic outside Svalbard. The knowledge we have of the Pleistocene history of Svalbard does not give much room for an endemic, comparatively thermophilous species like this one.
Elvebakk, A., Elven, R., Spjelkavik, S., Thannheiser, D. & Schweitzer, H.-J. 1994. Botrychium boreale and Puccinellia angustata ssp. palibinii new to Svalbard. – Polarflokken 18: 133–140.
Elvebakk, A. & Nilsen, L. 2002. Indre Wijdefjorden med sidefjorder: eitt botanisk unikt steppeområde. – Rapport Sysselmannen 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.
Hughes, W.E. & Halliday, G. 1980. Puccinellia Parl. – In: Tutin, T.G. et al. (eds.), Flora Europaea. 5. Alismataceae to Orchidaceae (Monocotyledones): 167–169.
Rønning, O.I. 1963. The Spitzbergen species of Colpodium Trin., Pleuropogon R. Br., and Puccinellia Parl. – Det Kongelige Norske Videnskabers Selskabs Skrifter 1961-4. 50 pp.