Phippsia algida (Solander) R. Brown

Desjardins, Émilie, Lai, Sandra, Payette, Serge, Dubé, Martin, Sokoloff, Paul C., St-Louis, Annie, Poulin, Marie-Pier, Legros, Jade, Sirois, Luc, Vézina, François, Tam, Andrew & Berteaux, Dominique, 2021, Survey of the vascular plants of Alert (Ellesmere Island, Canada), a polar desert at the northern tip of the Americas, Check List 17 (1), pp. 181-225 : 207

Phippsia algida (Solander) R. Brown

Figure 11F

Materials examined. CANADA – Nunavut • Ellesmere Island, CFS Alert; 82°26′40″N, 062°43′09″W; 210 m a.s.l.; 14 Jul. 2019; habitat: mesic, with peat and rocks as substrates, dominated by Juncus biglumis , moss, and blue-green algae (macroscopic sheet colonies dominated by Nostoc sp. ); QFA 0635538 • same locality; 82°25′52″N, 062°07′49″W; 296 m a.s.l.; 16 Jul. 2019; habitat: wetland in a mountain pass, with peat and rocks as substrates, dominated by moss and Saxifraga cernua ; QFA 0635539.

Identification. Plants 3.5–6.0 cm high; herbaceous; caespitose. Fibrous roots present. Stems 2.5–4.0 cm long; erect, ascending, or decumbent; glabrous. Leaves

basal and cauline. Sheath margins glabrous. Ligules 0.8–1.0 mm long. Basal leaf blades 8–20 mm long, 0.8– 1.2 (1.5–2.8 flat) mm wide; linear; folded or flat; abaxial and adaxial surfaces both glabrous; margins glabrous. Flag leaf blades 6–13 mm long, 0.7–1.2 (1.7–2.1 flat) mm wide. Inflorescence a dense panicle; 9–20 mm long. Branches at lowest inflorescence node 4–6; 1.0– 2.8 mm long. Pedicels glabrous. Spikelets 1.6–2.3 mm long, 0.8– 1.1 mm wide. Floret per spikelet 1. First glumes 0.3– 0.5 mm long; ovate; surface glabrous; margins glabrous; apices obtuse. Second glumes 0.4–0.7 mm long (shorter than the lowest floret); ovate; veins indistinct; surface glabrous; margins glabrous; apices obtuse. Lemmas 1.4–2.0 mm long, 0.7–1.1 mm wide; ovate; rounded on the back; veins 1–3; surface dull, glabrous, and hairy, with hairs on and between the veins proximally (hairs 0.07–0.17 mm long; covering the lower ½ of the lemma surface); apices acute or erose, and glabrous; awnless. Palea 1.3–1.9 mm long; veins hairy. Androecium with 1 or 2 stamens and 0.4–0.6 mm long anthers. Gynoecium with 2 styles. Fruit a caryopsis; 1.4–1.5 mm long, 0.3– 0.5 mm wide; ellipsoid.

Most authors recognize two Phippsia (Trinius) R. Brown species , P. algida and P. concinna (Th. Fries) Lindeberg ( Steen et al. 2004; Aiken et al. 2007; Consaul and Aiken 2007), although Soreng and contributors (2003) treated the latter taxon as Phippsia algida subsp. concinna (Th. Fr.) Á. Löve & D. Löve ; both taxa are known from Ellesmere Island. The most reliable characters to differentiate the species are the number of stamens (1 or 2 stamens in P. algida and 1 stamen in P. concinna ); caryopsis shape (ellipsoid in P. algida and ovoid in P. concinna ); pedicel angle (5–8° in P. algida and 20–108° in P. concinna ); lemma hairiness (hairs on lower 1/3 or entirely glabrous in P. algida and hairs on the 1/2–2/ 3 in P. concinna ); and lemma hair length (0.02–0.15 mm long in P. algida , and 0.19–0.24 mm long in P. concinna ; Aares et al. 2000). In addition, P. algida has spikelets that are less than twice as long as wide, whereas P. concinna has spikelets 2–3 times longer than wide (Consaul and Aiken 2007). We found that the lemmas of the P. algida specimens from Alert had longer hairs (up to 0.17 mm long) on a larger surface (½ of the surface) than reported in the literature.

Phippsia algida can also be mistaken for the hybrid × Pucciphippsia vacillans , which is also known from Alert and is somewhat intermediate between Phippsia algida and Puccinellia vahliana ( Hedberg 1962; Steen et al. 2004). They both have very short glumes (≤ 0.8 mm long; Aiken et al. 2007), but × P. vacillans differs from P. algida by having longer leaf blades (≥ 30 mm long), more than one floret per spikelet, and panicles with predom- inantly ascending branches, not erect as in P. algida ( Aiken et al. 2007) .