Draba subcapitata Simmons

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 : 194

Draba subcapitata Simmons

Figure 5F

Materials examined. CANADA – Nunavut • Ellesmere Island, CFS Alert ; 82°28′51″N, 062°10′58″W; 86 m a.s.l.; 15 Aug. 2019; habitat: xeric, with till and rocks as substrate, and sparse dominance of Saxifraga oppositifolia ; QFA0635585 , CAN .

Identification. Plants 1–2 cm high; herbaceous; caespitose. Taproots present. Stems 0.5–1.5 cm long; erect or ascending; hairy, with simple and branched hairs (2–4 rays: T, V, and dendritic). Leaves basal; alternate or whorled; petiolate or subsessile. Petioles 1.0– 1.5 mm long; slightly winged; margins glabrous or ciliate, with simple hairs. Basal leaf blades 3.7–5.0 mm long, 1–2 mm wide; linear or narrowly obtrullate; bases attenuate; midvein prominent; abaxial surface glabrous or sparsely hairy, with simple and branched hairs (2 rays: Y and T); adaxial surface glabrous; margins slightly revolute and ciliate, with simple long hairs; apices acute or obtuse. Inflorescence a raceme, with 2 or 3 flowers; not or slightly elongating as the fruit matures. Pedicels 1–2 mm long; hairy. Sepals 4; 1.2–1.6 mm long, 0.7–0.8 mm wide; ovate or oblong; green or purple, with hyaline margins; surface hairy, with simple hairs; margins glabrous; apices obtuse. Petals 4; 1.3–2.2 mm, long; 0.8–1.1 mm wide; obovate; unlobed, slightly lobed, or undulating; white. Androecium with 6 stamens and 0.3–0.4 mm long anthers. Gynoecium with 1 style and 1 stigma. Fruit a silique; 3–5 mm long, 2.0– 2.3 mm wide; ovate or elliptic; slightly bulged; dark purple; glabrous or sparsely hairy, with simple hairs. Styles persisting in fruit 0.05–0.30 mm long, 0.2–0.3 mm wide. Stigmas 0.2–0.3 mm wide; as wide as the styles.

Draba subcapitata differs from the five other whiteflowered Draba species present on Ellesmere Island ( Aiken et al. 2007; GBIF 2020) by having smaller petals (≤ 2.5 mm long and ≤1.0 mm wide; in contrast to D. arctica , D. cinerea , D. fladnizensis , D. lactea , D. nivalis ; Aiken et al. 2007), and by the combination of predominantly simple and branched hairs (2–4 rays) on leaves and stems (in contrast to the presence of hairs with>4 rays in D. arctica , D. lactea , and D. nivalis ; Garneau and Sabourin 2018).

Caryophyllaceae – Pink family