This South Asian species is a widespread weed in partial shade on moist soil, especially where exposed to grazing by cattle, which avoid eating the plant. Flowers are nearly regular, relatively large, with corollas 3-6 mm long and bracts about as long, along showy spikes P. frutescens is a strongly aromatic herb that has much traditional culinary use, but there can also be adverse reactions in mammals (Cr; Kerr et al. 1986). The distinctive flavor of this species is due to various terpenoids and allied ketones, which are toxic in some cases, causing pulmonary edema in large doses (Müller-Waldeck et al. 2010). Most colls. from Ky. appear to be the typical variety (F, W). There is also an unconfirmed record (Davies 1955) of var. crispa (Benth.) Dean, which has leaves that tend to be more deeply purple, somewhat laciniate and undulate-margined. This variant (or cultivar) became associated especially with Japanese cuisine (as "shiso" or "Japanese basil"), but it is also widely used across southeast Asia.