Survey of the vascular plants of Alert (Ellesmere Island, Canada), a polar desert at the northern tip of the Americas Author Desjardins, Émilie Author Lai, Sandra Author Payette, Serge Author Dubé, Martin Author Sokoloff, Paul C. Author St-Louis, Annie Author Poulin, Marie-Pier Author Legros, Jade Author Sirois, Luc Author Vézina, François Author Tam, Andrew Author Berteaux, Dominique text Check List 2021 2021-02-09 17 1 181 225 http://dx.doi.org/10.15560/17.1.181 journal article 10.15560/17.1.181 1809-127X Poa abbreviata R. Brown subsp. abbreviata Figures 10D, E , 11G Materials examined. CANADA – Nunavut • Ellesmere Island , CFS Alert ; 82°29′43″N , 61°57′15″W ; 14 m a.s.l. ; 30 Jul. 2019 ; habitat: xeric in a slope, with till and rocks as substrates, and sparse dominance of Salix arctica ; QFA0635535 • same locality; 82°28′11″N , 062°05′06″W ; 118 m a.s.l. ; 18 Jul. 2019 ; habitat: mesic, with polygonal patterned ground made of till and rocks, dominated by Stellaria longipes ; QFA0635536 . Identification. Plants 5.0– 9.5 cm high; herbaceous; caespitose. Fibrous roots present. Stems 4–8 cm long; erect or ascending; glabrous. Leaves basal and cauline. Sheath margins glabrous. Ligules 0.7–1.0 mm long. Basal leaf blades 12–41 mm long, 0.2–0.8 mm wide; linear; folded or rolled in bud; abaxial and adaxial surfaces both glabrous; margins scabrous or glabrous. Flag leaf blades 3.7–11.0 mm long, 0.3–0.8 mm wide. Inflorescence a dense panicle; 10–21 mm long. Branches at lowest inflo- rescence node 1–2; 2.1–3.5 mm long. Pedicels glabrous. Spikelets 4.7–5.4 mm long, 1.8–2.4 mm wide. Florets per spikelet 2–4. First glumes 3.0– 3.4 mm long; lanceolate; surface glabrous; margins glabrous; apices acuminate or acute. Second glumes 3.3–4.1 mm long (almost as long as the lowest floret); lanceolate or ovate; veins 1–3; surface glabrous; margins glabrous; apices acuminate or acute. Lemmas 3.3–3.8 mm long, 0.8–1.1 mm wide; lanceolate; keeled; veins 5; surface dull and hairy proximally on the 3/4 of the surface, with hairs on and between the veins; apices obtuse or erose, and glabrous; awnless. Palea 2.7– 3.3 mm long; veins scabrous. Rachilla between first and second lemmas 0.5–1.1 mm long. Androecium with 3 stamens and 0.7–1.2 mm long anthers. Gynoecium with 2 styles. There are five Poa Linnaeus species on Ellesmere Island ( P. abbreviata subsp. abbreviata , P. arctica R. Brown subsp. arctica and subsp. caespitans Simmons ex Nannfeldt , P. glauca Vahl subsp. glauca , P. hartzii Gandoger subsp. hartzii , and P. pratensis Linnaeus subsp. alpigena (Lindman) Hiitonen and subsp. colpodea (Th. Fries) Tzvelev ; GBIF 2020). Among them, only P. arctica subsp. arctica and the two P. pratensis subspecies have rhizomes ( Saarela et al. 2020 ). P. abbreviata subsp. abbreviata differs from the remaining caespitose species lacking rhizomes ( P. arctica subsp. caespitans , P. glauca subsp. glauca , P. hartzii subsp. hartzii ) by having in general a shorter inflorescence (≤ 2.2 cm long) in contrast to inflorescences reaching up to 6 cm long in the other spe- cies ( Aiken et al. 2007 ) and by having well developed and shorter anthers ( 0.1–1.2 mm long) in contrast to well developed or aborted, 1.0– 2.5 mm long anthers ( Saarela et al. 2020 ).