Taraxacum phymatocarpum J. Vahl

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 : 189

Taraxacum phymatocarpum J. Vahl

Figure 4

Materials examined. CANADA – Nunavut • Ellesmere Island, CFS Alert ; 82°27′48″N, 062°47′33″W; 14 m a.s.l.; 8 Jul. 2019; habitat: river delta, with silty sand and rocks as substrates; QFA0634995 .

Identification. Plants 2.5–5.5 cm high; herbaceous; not caespitose. Taproots present. Stems 1.5–4.0 cm long; ascending or erect; glabrous. Leaves basal; horizontal or patent; alternate; petiolate. Petioles 2–7 mm long; winged; glabrous. Leaf blades 5–25 mm long, 1–6 mm wide; oblanceolate; unlobed or dentate, with 1–3 triangular, acute lobes on each side; dark green; abaxial and adaxial surfaces both glabrous; margins glabrous; apices obtuse or acute. Calyculi 1.5–5.0 mm long; appressed or spreading; ovate; dark green or dark purple; surface glabrous; apices acute. Phyllaries 7–15 mm long; appressed; lanceolate; dark green or dark purple; surface glabrous. Inflorescence a solitary capitulum; 13–20 mm wide; with 30–40 zygomorphic florets. Sepals represented by pappi; 4–7 mm long; pale yellow or white. Petals 5; fused; pale yellow. Ray floret limbs 6–12 mm long, 1–4 mm wide; ligulate. Androecium with 5 stamens and 3–5 mm long anther tubes. Gynoecium with 1 style and 2 stigmas. Fruit an achene.

Taraxacum phymatocarpum can be differentiated from the three other Taraxacum F.H. Wiggers species present on Ellesmere Island ( T. ceratophorum (Ledebour) de Candolle , T. holmenianum Sahlin , and T. hyparcticum Dahlstedt ; Aiken et al. 2007; GBIF 2020) by the following: plant height <10 cm; flowering head small (15–20 mm wide); petals yellow without pink-grey stripes (as in T. hyparcticum ); and ligulate floret limbs ≤ 9 mm wide ( Brouillet 2006; Aiken et al. 2007).

Brassicaceae – Draba family

Braya purpurascens (R. Brown) Bunge ex Ledebour Syn. : Braya glabella Richardson subsp. purpurascens (R. Brown) Cody

Figure 5A

Materials examined. CANADA – Nunavut • Ellesmere Island, CFS Alert ; 82°28′11″N, 062°41′60″W; 154 m a.s.l.; 14 Aug. 2019; habitat: xeric, with polygonal patterned ground made of till and rocks, and sparse dominance of Saxifraga oppositifolia Linnaeus ; QFA0635558

• same locality; 82°29′46″N, 062°44′07″W; 30 m a.s.l.; 4 Jul. 2019; habitat: barren ground in a slope, with till and rocks as substrates, and sparse dominance of Saxifraga oppositifolia ; QFA0635559 • same locality; 82°27′48″N, 062°47′33″W; 14 m a.s.l.; 8 Jul. 2019; habitat: river delta, with silty sand and rocks as substrates; QFA0635560 .

Identification. Plants 1.5–4.5 cm high; herbaceous; caespitose. Taproots present. Stems 0.5–4.0 cm long; erect, ascending, or decumbent; hairy, with simple and branched hairs (2 rays: Y, T, and V). Leaves basal; alternate; petiolate. Petioles 2–5 mm long; winged; margins ciliate, with simple hairs. Leaf blades 4–19 mm long, 0.8–2.7 mm wide; linear or oblanceolate; unlobed or lobed, with 1–2 triangular acute lobes on each side; bases attenuate; abaxial and adaxial surfaces both shiny (living specimens) and glabrous; margins ciliate, with simple hairs; apices acute or obtuse. Inflorescence a cor- ymbiform raceme, with 2–6 flowers; not elongating or slightly elongating as the fruit matures. Pedicels glabrous or sparsely hairy. Sepals 4; 1.7–2.9 mm long, 0.8– 1.9 mm wide; ovate or oblong; purple; surface glabrous; margins glabrous or ciliate, with simple hairs; apices rounded. Petals 4; 2.4–3.8 mm long, 0.8–1.6 mm wide; obovate or obtrullate; unlobed; white and purple-tinged proximally. Androecium with 6 stamens and 0.3–0.5 mm long anthers. Gynoecium with 1 style and 1 stigma. Fruit a silique; 5.0– 10.2 mm long, 1.5–3.0 mm wide; elliptic or oblanceolate; cylindrical; yellowish purple or greyish green; surface glabrous or sparsely hairy, with simple and branched hairs (2 rays: T and V). Styles are persisting in fruit 0.7–1.2 mm long, 0.2–0.4 mm wide. Stigmas 0.5–0.7 mm wide; larger than the styles.

Braya Sternberg & Hoppe species can be differenti- ated from white-flowered Draba Linnaeus species by the terete or ovoid fruits; ciliate sepal margins; and presence of simple and 2-forked hairs on the leaves ( Aiken et al. 2007; Saarela et al. 2020). Among the four Braya species present on Ellesmere Island ( GBIF 2020), B. purpurascens , B. thorild-wulffii Ostenfeld subsp. thorild-wulffii , and B. glabella subsp. glabella and subsp. prostrata J.G. Harris have one or no cauline leaf and ovoid to cylindrical-elliptic fruits, whereas B. humilis (C.A. Meyer) B.L. Robinson subsp. humilis and subsp. ellesmerensis J.G. Harris have more than one cauline leaf and linear fruits ( Aiken et al. 2007; Harris 2010; Saarela et al. 2020). B. thorild-wulffii subsp. thorild-wulffii and B. glabella subsp. prostrata have decumbent to prostrate stems, whereas B. purpurascens and B. glabella subsp. glabella have erect or ascending stems ( Harris 2006, 2010). B. thorild-wulffii subsp. thorild-wulffii has short styles persisting in fruits (0–1 mm long), whereas B. purpurascens and both B. glabella subspecies have mostly longer styles (0.3–2.0 mm long; Harris 2006, 2010). The fruits of B. purpurascens and both B. glabella subspecies are oblong, ovoid-elliptic, or cylindrical-lanceolate, whereas they are ovoid or globose in B. thorild-wulffii subsp. thorild-wulffii ( Harris 2006; Saarela et al. 2020). Fruits of B. glabella subsp. glabella are oblong or narrowly oblong-lanceoloid, often curved, and 3.5–8.3 times as long as wide, whereas they are ovoid-elliptic or oblong-elliptic, usually straight, and 2.5–3.7 times as long as wide in B. purpurascens and B. glabella subsp. prostrata ( Harris 2010) .