Annual herb with a long taproot 10 - 30 cm tall Stem: upright, branched above, with a waxy coating (glaucous). Flowers: in compact, branched clusters (racemes), which are borne terminally on the stems. Flower stalks to 4 mm long (longer in fruit). Sepals four, ascending, green with whitish margins, to 1.5 mm long, to 1 mm wide. Petals four, white, 2 - 3 mm long. Stamens six. Anthers yellow. Fruit: a pod (silicle), 4 - 7 mm long, egg-shaped with narrowed base and rounded tip, tips notched (wider than deep), winged. Fruit stalks horizontally spreading, to 6 mm long. Seeds two to four per chamber. Basal leaves: in a rosette, stalked, to 3 cm long, to 1.5 cm wide, egg-shaped or oblong or elliptic, coarsely toothed. Leaf stalks to 2 cm long. Stem leaves: alternate, stalkless, clasping, 1 - 3 cm long, progressively reduced, egg-shaped to oblong egg-shaped with rounded lobes at the base, sometimes coarsely toothed, with a waxy coating (glaucous).
Similar species: No information at this time.
Flowering: June to July
Habitat and ecology: Introduced from Eurasia. An uncommon weed of roadsides, railroads, waste ground, fields, and disturbed areas.
Occurence in the Chicago region: non-native
Etymology: Thlaspi is the Greek word for cress. Perfoliatum means "with the leaf surrounding the stem."
Annual 1-3 dm; cauline lvs sessile, ovate or ovate- oblong, 1-3 cm, entire or with a few teeth, the basal auricles blunt or rounded; pet 2-3 mm; mature pedicels horizontally spreading; frs obovate, 4-7 mm; convex below, the wing gradually widening to the summit, the wide open notch ca 0.5-1 mm deep and 1-2 mm wide; seeds smooth, 2-4 per locule; 2n=14, 28, 42, 70. Native of Eurasia, now found in fields, roadsides, and waste places here and there in our range. Apr., May.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.