Wallflowers are annual to perennial herbs with alternate, entire to strongly wavy-edged and toothed leaves. The surface is sparsely to densely covered with flat, stiff, short hairs which are mostly 2-rayed, but with a variable amount of 3- and 4-rayed hairs, that are oriented with the axis of the leaf or stem on which they occur. The flowers are rather showy, borne in non-bracted, usually crowded elongated clusters. The 4 sepals are erect, sometimes touching, the 2 outer ones usually pouched at the base. The 4 petals are lemon-yellow to golden or more nearly orange or reddish, with long, narrowed stalks, often softly short-hairy on the back. There are 6 stamens. The fruit is elongate, linear, with strongly nerved valves, from flattened to cylindrical or 4-angled in section. The style is rather prominent, 1-4 mm long, often beaklike. The stigma is 2-lobed. The seeds are in 1 series, wingless to flattened and wing-edged, not becoming slimy when wet. The genus consists of about 80 species of the N. Temperate Zone, mostly Eurasian. The name comes from the Greek name, erusimon, for the plant, said to be derived from eryo, to draw, some of the species being used as mustard to produce blistering.
Guide to Identify Presented Species of Genus Erysimum
FLOWERS LARGE, 15 MM BROAD OR MORE
E. capitatum Western Wallflower Mostly flat-hairy plants with showy flowers. Leaves many, alternate, narrowly lance-shaped. Fruit pods linear, thin, cylindrical, 3-10 cm long.