Glandularia

Glandularia (common name mock vervain or mock verbena) is a genus of annual and perennial herbaceous flowering plants in the family Verbenaceae. They are native to the Americas.

Glandularia species are closely related to the true vervains and sometimes still included with them in Verbena. Horizontal chloroplast transfer occurred at least twice and possibly three times between these genera, which are otherwise too distinct to warrant unification. The discovery of the signal in the chloroplast genome was announced in 2008 by researchers from the University of Washington. Somehow, chloroplasts from V. orcuttiana, swamp verbena (V. hastata) or a close relative of these had admixed into the G. bipinnatifida germline. Although hybridization runs rampant in the true and mock vervains – the ancestors of the well-known garden vervain are quite obscure – it does not seem to have been the cause of the cross-species gene transfer.