Deschampsia cespitosa (Linnaeus) Palisot de Beauvois subsp. septentrionalis Chiapella

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 : 202-204

Deschampsia cespitosa (Linnaeus) Palisot de Beauvois subsp. septentrionalis Chiapella

Syn.: Deschampsia brevifolia R. Brown

Figure 11A

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 till as substrates, dominated by Juncus biglumis , moss, and blue-green algae (macroscopic sheet colonies dominated by Nostoc sp. ); QFA 0635545 • same locality; 82°29′58″N, 062°33′46″W; 65 m a.s.l.; 6 Jul. 2019; habitat: mesic, with polygonal patterned ground made of till, dominated by Alopecurus magellanicus and moss; QFA 0635546.

Identification. Plants 4–10 cm high; herbaceous; caespitose. Fibrous roots present. Stems 2–8 cm long; erect; glabrous. Leaves basal and cauline. Sheath margins glabrous. Ligules 2.6–3.7 mm long. Basal leaf blades 15– 45 mm long, 0.4–1.1 mm wide; linear; rolled in bud or

folded; abaxial surface glabrous; adaxial surface scabrous and hairy, with few short hairs apically; margins scabrous. Flag leaf blades 11.0– 13.3 mm long, 0.5– 0.6 (1.0–1.1 flat) mm wide. Inflorescence a dense pan- icle; 17–22 mm long. Branches at lowest inflorescence node 3–4; 1.8–6.2 mm long. Pedicels glabrous. Spikelets 3.6–4.9 mm long, 0.6–1.8 mm wide. Florets per spikelet 1–2. First glumes 2.7–3.1 mm long; lanceolate; surface glabrous; margins glabrous; apices acuminate or acute. Second glumes 2.8–3.4 mm long (almost as long as the lowest floret); lanceolate; veins 1–3; surface gla- brous; margins glabrous; apices acute. Lemmas 2.7–3.1 mm long, 0.5–0.7 mm wide; lanceolate; keeled; veins 5; surface shiny, glabrous, and hairy, with long hairs only at the base; apices acute or erose, and glabrous; awned. Awns 1.0– 1.4 mm long; arising from the middle or below. Palea 1.8–2.6 mm long; veins scabrous. Rachilla between first and second lemmas 0.9–2.1 mm long. An- droecium with 3 stamens and 0.9–1.4 mm long anthers. Gynoecium with 2 styles.

Deschampsia brevifolia and D. sukatschewii (Poplavskaja) Roshevitz are the two Deschampsia Palisot de Beauvois species on Ellesmere Island ( Aiken et al. 2007; GBIF 2020). They can be differentiated by the following: D. brevifolia has dense panicles with strongly imbricate spikelets, whereas D. sukatschewii usually has open panicles with no or only moderately imbricate spikelets ( Barkworth 2007; Saarela et al. 2020); the glumes and lemmas of D. brevifolia are usually dark purple proximally for over>½ of their surface, whereas they usually are dark purple proximally over <½ of their surface in D. sukatschewii ( Barkworth 2007; Saarela et al. 2020); D. brevifolia has keeled lemmas, whereas D. sukatschewii has rounded on the back lemmas ( Aiken et al. 2007); and D. brevifolia has scabrous palea veins, whereas D. sukatschewii has glabrous palea veins ( Aiken et al. 2007).