Cardamine flexuosa
Cardamine rotundifolia
wavy bitter-cress, wood bitter-cress, woodland bitter-cress
American bittercress, mountain watercress
absent.
slender, to 2 mm diam.
erect, ascending, or decumbent, branched or unbranched, (0.6–)1–5 dm, (slightly flexuous).
usually procumbent, sometimes erect, (not flexuous), unbranched or branched, (1–)1.5–3(–5) dm.
(often withered by anthesis), not rosulate, 5–15-foliolate, (2.7–)4–14(–19) cm, leaflets petiolulate;
petiole 0.7–5 cm, (ciliate or not);
lateral leaflet blade oblong, ovate, or elliptic, smaller than terminal, margins entire, repand, crenate, or 3 (or 5)-lobed;
terminal leaflet (petiolule 0.3–1.7 cm), blade reniform, broadly ovate, or suborbicular, 0.5–2.5 cm × 4–30 mm, margins repand, crenate, or 3 or 5-lobed.
(soon withered), not rosulate.
absent.
3–15, 5–15-foliolate [leaves (2–)3.5–5.5(–7) cm, including petiole], petiolate, leaflets petiolulate;
petiole base not auriculate;
lateral leaflets similar to basal, (0.4–2.5 mm wide).
simple, petiolate;
petiole (0.3–)0.5–2.5(–4) cm, base not auriculate;
blade oblong, ovate, suborbicular, or cordate, (0.5–)1–4.5(–5.5) cm × (5–)10–40(–54) mm, base cordate, rounded, or truncate, margins entire, repand, or sinuate, (distally with shorter petiole, blade smaller).
ebracteate.
ebracteate.
sepals oblong, 1.5–2.5 × 0.7–1 mm, lateral pair not saccate basally;
petals white, spatulate, 2.5–4(–5) × 1–1.7 mm; (stamens rarely 4, lateral pair absent);
filaments 2–3 mm;
anthers ovate, 0.3–0.5 mm.
sepals oblong, 2–3 × 1–1.7 mm, lateral pair not saccate basally;
petals white, broadly oblanceolate, spreading, 5–7(–8) × 2–3 mm, (not clawed, apex rounded);
filaments: median pairs 3.5–4.5 mm, lateral pair 2.7–3.5 mm;
anthers oblong, 0.8–1.2 mm.
divaricate or ascending, (5–)6–14(–17) mm.
divaricate to ascending, (6–)10–15(–20) mm.
linear, (torulose), (0.8–)1.2–2.8 cm × 1–1.5 mm;
ovules 18–40 per ovary;
style 0.3–1(–1.5) mm.
linear, (torulose), 1–1.5(–2) cm × 0.8–1.1 mm;
ovules 40–80 per ovary;
style 1.5–2.5 mm.
brown, oblong or subquadrate, 0.9–1.5 × 0.6–1 mm, (narrowly margined or not).
brown, oblong to ovoid, 0.9–1.1 × 0.5–0.6 mm.
= 32.
Cardamine flexuosa
Cardamine rotundifolia
According to J. Lihová et al. (2006), the populations referred to Cardamine flexuosa in North America comprise two taxa of different polyploid origins and evolutionary histories: tetraploid C. flexuosa (2n = 32), native to Europe, and the octoploid taxon informally called “Asian C. flexuosa” (2n = 64), native to eastern Asia. For the latter, the name C. flexuosa subsp. debilis can be used. Nevertheless, these two taxa should be recognized at species level and the correct name for the Asian species should be sought. Based on available data, both taxa occupy the same habitats in North America, but the Asian taxon is much more widespread. The occurrence of European C. flexuosa was, until now, confirmed only for Washington, where both taxa have been recorded. More detailed studies of the North American distributions of both these weeds are needed.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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