Di Huang

Rehmannia glutinosa is a sticky-glandular herbaceous perennial in the Orobanchaceae (formerly placed in Scrophulariaceae), native to northern and central China and adjacent parts of Korea and Japan, where it grows on dry, sunny slopes, roadsides and field margins on loose sandy or loamy soils. Plants grow 15-40 cm tall from clusters of fleshy, fusiform, orange-red taproots that ooze a sticky juice when cut. The whole plant is covered in long, soft, sticky, glandular hairs that give it a velvety, slightly clammy feel. The basal rosette leaves are obovate to oblong, 3-12 cm long, with shallowly toothed to crenate margins and a coarsely reticulate, deeply impressed venation on the wrinkled upper surface. The flowering stems bear loose racemes of showy, drooping, tubular-bell-shaped flowers about 4 cm long, reddish-purple to dull pink-brown outside and yellow to violet with darker veining inside.