Cardaria draba (L.) Desv.
Family - Brassicaceae
Stems - To +40cm tall, erect, herbaceous, typically multiple from base, from thick taproot, typically simple but branching in inflorescence, densely retrorse puberulent below, sparse puberulent above, ribbed from decurrent leaf tissue.
Leaves - Alternate, sessile, oblong to lanceolate or ovate, to +6.5cm long, 3cm broad, reduced above, dentate to serrate, slightly undulate, clasping, auriculate, acute, densely pubescent. Auricles rounded or pointed, +/-7mm long.
Inflorescence - Multiple terminal racemes in a terminal corymbose arrangement. Pedicels filiform, expanding in fruit to +/-1.5cm long, glabrous.
Flowers - Petals 4, white, free, clawed, glabrous, typically spreading, to +/-3mm long. Limb rotund to broadly obovate, +1.5m in diameter. Stamens 6, erect to spreading. Filaments +/-3mm long, white, glabrous. Anthers yellow-orange, .5mm long. Nectaries present at base of stamens and surrounding ovary. Style 1mm long, yellowish-green. Stigma capitate, globose. Ovary superior, compressed, ovoid, yellowish-green, glabrous, 1.8mm long in flower. Sepals 4, free, whitish-green with broad scarious margins, to 2mm long, 2mm broad at apex, obovate to spatulate. Silicles to 3mm long, +3mm broad, cordate.
Flowering - April - June.
Habitat - Waste ground, slopes, roadsides, railroads.
Origin - Native to Europe.
Other info. - Still another introduced member of the Brassicaceae. This species is becoming common in Missouri but is not found throughout the state yet. The plant is easy to ID in the field because of its clasping dentate leaves and crowded, mostly flat-topped, inflorescences. Large colonies of this species can occur when the plants are left undisturbed.
Photographs taken off Farley Road, Platte County, MO., 5-5-01.