Saxifraga flagellaris Willdenow subsp. platysepala (Trautvetter)

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 : 218-219

Saxifraga flagellaris Willdenow subsp. platysepala (Trautvetter) A.E. Porsild

Figure 17E

Materials examined. CANADA – Nunavut • Ellesmere

Island, CFS Alert; 82°27′17″N, 062°35′55″W; 166 m a.s.l.; 11 Jul. 2019; habitat: mesic in a slope; QFA 0635003.

Identification. Plants 1.5–6.0 cm high; herbaceous; not caespitose. Fibrous roots and stolons present. Stolons 25–80 mm long; filiform; red; hairy, with glandu- lar hairs; leafless; terminating in a tiny rosette attached to the substrate by adventitious roots. Stems 1.0– 5.5 cm long; erect; hairy, with glandular hairs. Leaves basal and cauline; heterophyllous; alternate; subsessile (basal leaves) or sessile (cauline leaves). Basal leaf blades 3–8 mm long, 2.0– 4.5 mm wide; obovate or obtrullate; unlobed; red or green; abaxial and adaxial surfaces both glabrous; margins ciliate, with long stiff glandular hairs; apices obtuse. Cauline leaf blades 4–6 mm long, 1–2 mm wide; abaxial surface sparsely hairy, with glandular hairs; adaxial surface glabrous; margins ciliate; apices rounded or obtuse. Inflorescence a solitary flower. Se- pals 5; 3–6 mm long, 1.5–2.5 mm wide; ovate; green to purple; surface hairy, with glandular hairs; margins ciliate; apices obtuse. Petals 5; 4–10 mm long, 2.5–6.0 mm wide; obovate; unlobed; yellow. Androecium with 9–10 stamens and 0.5–0.9 mm long anthers. Gynoecium with 2 styles. Fruit not seen at Alert.

Among the three Saxifraga species present on Ellesmere Island with entire basal leaves and yellow petals ( S. aizoides , S. flagellaris subsp. platysepala , and S. hirculus ; GBIF 2020; Saarela et al. 2020), S. flagellaris subsp. platysepala differs from the two others by having red, long stolons and unspotted petals ( Saarela et al. 2020). S. aizoides and S. hirculus usually do not have stolons (but if present, the stolons are very short and green), but can have petals with orange spots ( Saarela et al. 2020).