The sequences of the plastid gene rpl16 and the rpl16-rpl14 spacer region allow discrimination among six species of Scutellaria.

Dried aerial parts of Scutellaria galericulata L. (Labiatae; marsh skullcap) and Scutellaria lateriflora L. (Labiatae; mad dog skullcap) are mainly used as skullcap, a medicinal herb, in Europe and the United States. The respective dried aerial parts of the two species are difficult to distinguish morphologically from each other. We attempted to discriminate among six species (Scutellaria altissima L. (Labiatae), Scutellaria baicalensis Georgi (Labiatae), Scutellaria galericulata, Scutellaria incana Spreng. (Labiatae), Scutellaria indica L. (Labiatae) and Scutellaria lateriflora) of Scutellaria, which include three medicinal species (Scutellaria galericulata, Scutellaria lateriflora and Scutellaria baicalensis), by comparing the respective nucleotide sequences of the plastid rpl16 gene and the rpl16-rpl14 spacer region. Comparisons of these sequences allowed us to identify each of the six species unequivocally.