4. Cardamine douglassii (Torr.) Britton (purple cress, northern bitter cress)
C. bulbosa (Schreb. ex Muhl.) Britton, Sterns & Poggenb. var. purpurea
(Torr.) Britton, Sterns & Poggenb.
Pl. 316 a, b;
Map 1334
Plants perennial herbs with short, tuberous, unsegmented rhizomes. Stems (7–)10–30
cm long, with spreading hairs (0.2–)0.3–0.6(–0.8) mm long, especially in the
apical half. Leaves 2–7 cm long, simple, entire, wavy-margined, or with few,
shallow, widely spaced teeth, often sparsely hairy; the basal leaves usually
withered by flowering time, long-petiolate, the leaf blades ovate to cordate;
the stem leaves mostly 3–5, mostly sessile, ovate to lanceolate or narrowly
elliptic. Sepals (2.5–)3.0–6.0 mm long, reddish purple. Petals (7–)8–14 mm
long, pink to purplish pink. Styles 3–4 mm long. Fruits (15–)25–40 mm long,
sometimes aborting before maturity. Seeds 1.7–2.1 mm long, irregularly oblong
to circular in outline, the surface slightly roughened, orange to greenish yellow.
2n=64, 96, 144. March–April.
Scattered in northeastern Missouri (eastern U.S. and adjacent Canada
west to Minnesota, and Missouri). Mesic to wet bottomland forests.
For a discussion of the separation between this species and the closely related
C. bulbosa, see the treatment of that species.