ABSTRACT
Lamium amplexicaule L. (Labiatae), an annual mint, is an agricultural weed introduced into California from Mediterranean areas. 1 The inflorescence contains both cleistogamous (closed, CL) flowers, which self in the bud, as well as chasmogamous (open, CH) flowers, which undergo anthesis and may outcross. This species is the only one of the genus Lamium which produces CL flowers, and as a result it is highly inbred. 2 - 5 The phenomenon of cleistogamy, whereby such dimorphic flowers are produced by an individual, occurs in at least 56 families. 6 - 8 It provides a means for both inbreeding and outcrossing for the species.
