Whitetops are softly short-hairy, often rhizome-bearing perennial herbs with simple, toothed, often arrow-shaped leaves. The flowers are inconspicuous, slender-stalked in dense, non-bracted, elongated to flat-topped clusters. The 4 sepals are falling off early. The 4 petals are white. There are 6 stamens. The fruit is an inflated pod, ovoid to rounded, somewhat flattened perpendicular to the partition, tardily splitting open or staying closed. The style is prominent and slender. There is usually a single seed (occasionally 2) per ovary cell. The seed is not wing-edged, but gets slimy when wet. This is a Eurasian genus of perhaps half a dozen species. All our species are noxious weeds. The name comes from the Greek kardia, heart, referring to the cordate fruit pods of some species.
Guide to Identify Presented Species of Genus Cardaria
FRUIT PODS HAIRLESS
C. chalapensis Lens-pod Whitetop Perennial, flowers small, in wide, dense clusters. Leaves alternate, oblanceolate, sharp-toothed. Fruit pods almost round, hairless, not cordate at base.