Contributed by Bruce A. Sorrie
A genus of about 100 species, hemiparasitic biennial and perennial herbs, of tropical and warm temperate regions of the Old and New Worlds. The taxonomy of this genus is poorly understood. The plants are root hemi-parasites, apparently not particular about the host species.
ID notes:Lower leaves are broadest, mid and upper leaves narrowest, often markedly so; the key refers to lower leaves. Leaf teeth are usually few in number and vary in development, from crenate to 2-3 mm long and sharply pointed. The former condition is normal for B. floridana, the latter for B. americana. Calyx length is ca. 0.5 mm longer in fruit than in flower. The foliage turns black on drying.