Solitary graminoid herb growing in dense tussocks with all branching inside the leaf sheaths (intravaginal). Tussocks mostly less than 10 cm in diameter but may occasionally reach 20 cm or more in manured sites. Aerial shoots with several, hyaline prophylls. Culms 2–4(8) cm, prostrate along the ground, rarely erect, smooth and glabrous. Base of culms with a loose sheath of pale yellow or whitish, withered leaves.

Leaves with keel, flat or folded (convolute), smooth and glabrous. Basal leaves 1–4 cm long, as long as culms or shorter, 1.5–3 mm broad, abruptly tapering into a short apex shaped like the bow of a boat. Culm leaves 1–2, similar to basal leaves but much shorter, 0.5–1(1.5) cm; flag leaf blade 0.3–1.0 cm, attached at middle of culm or below. Ligula 0.5–1.5 mm, acute.

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), and a gynoecium of 2 fused carpels with 2 feathery stigmas and one seed.

Inflorescence a dense (congested) to more open, ovoid to narrowly ellipsoid panicle, 0.5–2 cm long, occupying ca. 1/3 of culm length, green or often tinged with purple. Panicle with 4–6 nodes, with 3–6(9) branches at each of the lower nodes. Branches 5–15 mm, erect to ascending, smooth, each with numerous spikelets (ca. 10 or more on the longest branches). Spikelets 1.0–1.5 × 0.8–1.2 mm, less than 2 times as long as broad, with one flower. Bracts (glumes, when present, and lemmas) with rounded backs. Glumes minute, obtuse to acute, without veins, entirely hyaline or with a green or deep purple mid section, soon caducous. Lower glume 0.2–0.3 mm, upper glume 0.3–0.6 mm, both much shorter than 1/2 the length of the spikelet. Lemmas 1.4–1.6 mm, broadly ovate or obovate, obtuse or subacute, often fringed (erose), with 3 veins, glabrous or with a few short, stiff hairs in their lower 1/3, veins and mid section green or deep purple, otherwise and in the apical parts hyaline. Paleas similar to and as long as lemmas, with smooth keels. Stamens 1–2; anthers 0.3–0.7 mm.

Fruit an achene (with one seed), ellipsoid, widest at or just above the middle.

Sexual reproduction by seeds, no vegetative reproduction. The species is potentially wind pollinated but water pollination and self pollination (autogamy) probably predominates. Fruit production is usually abundant almost every year in most sites. Seeds germinate to ca. 2 % in an experiment (Alsos et al. 2013), a surprisingly low value as the closely related and physiognomically and ecologically similar P. concinna germinated to > 90 %. Some sampling or experimental error is suspected.

Fruits (inside florets) are mainly dispersed by water and probably by birds.

The two species of Phippsia are rather special and do not resemble many other grasses (except for the genus hybrid Pucciphippsia, i.e., Phippsia × Puccinellia). They differ from Pucciphippsia vacillans in 1-flowered spikelets, glumes absent or very reduced, and abundant fruit production. In Pucciphippsia the spikelets are mostly 2-flowered, the glumes small but distinct, and fruit-set not yet observed. They differ from the sometimes similar species of Puccinellia in their very small size and 1-flowered spikelets.

The main differences between the two species of Phippsia are: In P. algida the spikelets are less than 2 times as long as broad, the glumes fall off early, lemmas are glabrous or hairy only in their proximal part and green to slightly purplish, and the fruits are ellipsoid (broadest at or just above the middle); in P. concinna the spikelets are more than 2 times as long, at least the upper glume is long retained, lemmas are hairy for at least half their length and purplish throughout, and the fruits are narrowly ovoid (broadest below the middle and tapering towards apex). As you can see, the two most easily visible characters, the shape of the panicle (in P. algida congested and ovoid with erect or ascending branches, in P. concinna open and pyramidal with spreading or retrorse branches) and the direction of the culms (in P. algida usually prostrate, in P. concinna erect) are not on the list above. The reason is the ‘algidiformis’ plants commented on below. Steen (2000: 45) found 20 morphological characters (out of 40 studied) to distinguish significantly (p ≤ 0.05) between the two species, and 9 of these to distinguish highly significantly (p ≤ 0.001), even when the ‘algidiformis’ plants were included.

On open or sparsely moss-covered, fine-grained ground, often seasonally or periodically moist or wet. Usually found either in disturbed sites (e.g., flood plains, road verges), on shores (by freshwater and seashores) or on frost-patterned ground in snowbeds and on mountain plateaus. Indifferent as to soil reaction (pH). This is the species of Phippsia usually found in areas with acidic substrates.

Common in all zones and sections and on all major and most minor islands, including Bjørnøya and the islands north and east of Nordaustlandet (e.g., Kvitøya, the harshest environment on all of Svalbard where less than 10 vascular plants are known).

Phippsia algida is one of the most widespread of all arctic plants, circumpolar in the Arctic and also transgressing south in many mountains, in Europe only to S Norway but in North America far south in the Rockies.

The nomenclatural types of both Phippsia species are connected to Svalbard: P. algida probably from Lågøya north of Nordaustlandet (Phipps in 1774) and P. concinna from Svalbard and (Russian) Kolguev Island (Th. Fries in 1870). Neither species name seems to be supported by a lectotype yet. Even then, the morphology of Svalbard plants (and for P. concinna perhaps Kolguev) decides how the species names shall be applied.

There are three major questions concerning the two species of Phippsia: their relations to the much larger genus Puccinellia, their distinction from each other and possible hybridization, and their possible partaking in the hybridogeneous genus Pucciphippsia (also present in Svalbard with P. vacillans). For the last question, see Pucciphippsia. There are several studies concerned with all three questions, most recently summarized by Steen (2000) and Steen et al. (2004). See also Elven et al. (2011).

The genus Phippsia consists of only two species but is closely related and rather similar to the large genus Puccinellia (ca. 120 species according to Davis & Consaul 2007, more likely 200–300 species according to other authors). Two intergeneric hybrids between Phippsia and Puccinellia are known: Pucciphippsia vacillans (Th.Fr.) Tzvelev (see separate entry) and the Asian Beringian P. czukczorum Tzvelev. The majority of the distinguishing features in the spikelets of Phippsia could be viewed as reductions from a Puccinellia base, i.e., the 1-flowered spikelets, the reduced glumes, and the reduced number of stamens (1–2). If Phippsia is merged inside Puccinellia, Phippsia will be the priority name for such a merged genus (Phippsia (Trin.) R.Br. 1823 vs. Puccinellia Parl. 1850). Löve & Löve (1976) argued for this merger and recombined a majority of the northern species of Puccinellia as species of Phippsia (see the synonyms under Puccinellia). This merger has not won much acclaim. Note, however, that both species of Phippsia are tetraploid (2n = 28) and could be results from hybridization between Puccinellia and another genus. Tzvelev in Elven et al. (2011) commented: "Intergeneric hybrids are common in Poaceae. There is no reason to join Phippsia and Puccinellia." The majority of modern authors tend to follow Tzvelev here, e.g., Consaul & Aiken (2007) in Flora of North America.

Löve & Löve (1975) recombined Phippsia concinna as P. algida ssp. concinna (Th.Fr.) Á.Löve & D.Löve. Their reason for this is not very evident, but many authors before and since have assumed that transitional forms are common between P. algida and P. concinna, justifying a merger as subspecies of one species. These plants are very small and their characters may be difficult to observe, but as seen from the summary above and from Steen (2000), there are numerous characters to use. Steen investigated the variation in 28 populations (15 algida, 13 concinna) and 164 plants (89 algida, 75 concinna), of which 10 populations is the conclusions of the majority of previous investigators, particularly those familiar with the two species in field.

In an early study, Holmberg (1924) found an assumed, pollen sterile hybrid in material from C Norway and possibly a similar one in material from Svalbard (i.e., two individuals in the entire material available in the Scandinavian herbaria at that time). During decades of work in the Arctic and in nearby mountains, we have never seen a single suspected hybrid individual between the two species. It is therefore strange when Tzvelev (1971) argues that hybridization is very common and that P. × algidiformis is a hybridogeneous species between P. algida and P. concinna. This discussion is referred at length by Steen & Elven in Elven et al. (2011), and our three main conclusions are: (1) there are two distinct species with virtually no hybridization; (2) the ‘algidiformis’ of Tzvelev (1971) and other investigators in the Arctic is part of the variation within P. concinna; and (3) the true Catabrosa concinna ssp. algidiformis Harry Sm. is, at best, a local population group of depauperate (inbreeding?) plants in the Sylene–Helagsfjäll mountains in C Scandinavia, in an area where typical P. concinna and P. algida both are absent.

Even if the morphology is comparatively clear, Steen (2000) and Steen et al. (2004) found some strange molecular features in the isozymes. Their main focus was on elucidating Pucciphippsia vacillans but naturally also included the putative parents: Puccinellia vahliana, Phippsia algida and P. concinna. They found no difference whatsoever in isoenzymes between P. algida and P. concinna. There were two multilocus phenotypes (due to a polymorphy in IDH), but both were present in both species, one of these also in both Puccinellia vahliana and Pucciphippsia vacillans. Puccinellia vahliana was mainly negatively characterized as all its enzyme bands except one were present also in Phippsia. This single diagnostic band was shared with Pucciphippsia vacillans, supporting the hybrid hypothesis. Phippsia and Pucciphippsia shared several bands not present in Puccinellia vahliana. These isoenzyme data could now probably be refined by more differentiating methods.

Our conclusion is that the morphological distinction between the two Phippsias is clear, whereas the molecular distinction is absent in what has been studied until now. Also Aares et al. (2000) found little variation in a study based on two esterase markers.

The frequent appearance of the name "algidiformis" in arctic literature, in spite of its relevance probably restricted to a possibly inbreeding, depauperate population in a marginal part of the C Scandinavian mountains (see above), needs an explanation. This is readily found: Phippsia concinna appears in two morphs not separable in more detailed morphological characters (or in the molecular markers yet studied). Whereas typical P. concinna has a pyramidal panicle with spreading to retrorse branches, many populations have a congested panicle resembling that of P. algida but with the characters of P. concinna in spikelets, flowers and fruits. In Svalbard, both these morphs are common. East and south of Svalbard, the typical morph with the broad, pyramidal panicle is the common throughout arctic Russia and into the Bering Straits on St. Lawrence Island (but not into mainland North America), and south in the mountains in an isolated area in S–C Scandinavia. To the west of Svalbard, P. concinna has not been recognized from Greenland or arctic Canada until fairly recently when Bay (1993) reported P. concinna ssp. algidiformis from N Greenland and Consaul & Aiken (2007) accepted it from Canada in Flora of North America. There have been some voices before (Bowden in Savile 1959; Bowden 1960) but they were ignored. The reason for the very late acceptance of this species from North America including Greenland is just the polymorphy described above. Whereas Russian and Scandinavian plants belong to the typical P. concinna with pyramidal panicles, the Greenland and Canadian plants belong to the morph with congested, more ovoid panicles. Two races (subspecies) of P. concinna, meeting and mixing without much transitional forms in just Svalbard, might be justified, but morphological and molecular evidence supporting such a treatment is not available at present.

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.

Aares, E., Nurminiemi, M. & Brochmann, C. 2000. Incongruent phylogeographies in spite of similar morphology, ecology, and distribution: Phippsia algida and P. concinna (Poaceae) in the North Atlantic region. – Plant Systematics & Evolution 220: 241–261.

Bay, C. 1993. Taxa of vascular plants new to the flora of Greenland. – Nordic Journal of Botany 13: 247–252.

Bowden, W.M. 1960. Chromosome numbers and taxonomic notes on northern grasses. II. Tribe Festuceae. – Canadian Journal of Botany 38: 117–131.

Consaul, L.L. & Aiken, S.G. 2007. Phippsia (Trin) R. Br. – In: Flora of North America Editorial Committee (eds.), Flora of North America north of Mexico. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1: 478–480.

Davis, J.I. & Consaul, L.L. 2007. Puccinellia Parl. – In: Flora of North America Editorial Committee (eds.), Flora of North America north of Mexico. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1: 459–477.

Elven, R., Murray, D.F., Razzhivin, V. & Yurtsev, B.A. (eds.) 2011. Annotated Checklist of the Panarctic Flora (PAF) Vascular plants. http://panarcticflora.org/

Holmberg, O.R. 1924. Die Gattung Phippsia und ihre Arten. – Botaniska Notiser 1924: 126–134.

Löve, Á. & Löve, D. 1975. Nomenclatural adjustments in some European monocotyledons. – Folia Geobotanica et Phytotaxonomica 10: 271–276.

Löve, Á. & Löve, D. 1976. Nomenclatural notes on arctic plants. – Botaniska Notiser 128: 497–523.

Savile, D.B.O. 1959. The botany of Somerset Island, District of Franklin. – Canadian Journal of Botany 37: 959–1002.

Steen, N.W. 2000. A test of the hybrid origin hypotheses of Pucciphippsia vacillans (Poaceae) in Svalbard, by use of enzymatic, morphological and cytological data. – Cand. scient. thesis, Univ. Oslo, Oslo.

Steen, N.W., Elven, R. & Nordal, I. 2004. Hybrid origin of the arctic X Pucciphippsia vacillans (Poaceae): evidence from Svalbard plants. – Plant Systematics & Evolution 245: 215–238.

Tzvelev, N.N. 1971. Zametki o zlakach flory SSSR, 6. – Novosti Sistematiki Vysshykh Rastenii 8: 57–83.