Morphological and molecular phylogenetic analyses conducted over the past 20 years have helped clarify the composition of Lamiaceae, but the circumscription of major sublineages within Lamiaceae is unclear, and the phylogenetic backbone of the family remains poorly resolved. This lack of resolution hinders our ability to characterize patterns of diversification, biogeography, and character evolution and to infer evolutionary processes within the family.
Despite recognition of core Lamiaceae for centuries, the family was only recently defined in its current broad sense (Cantino & Sanders 1986; Cantino 1992; Wagstaff et al. 1995, 1998; Wagstaff & Olmstead 1997; Harley et al. 2004; see also Junell 1934); despite recognizable features – quadrangular stems, opposite leaves, and hypogynous flowers – that are nearly ubiquitous in the family, the only clear synapomorphy is a unique ovary anatomy. Although Lamiaceae, as delimited by Cantino (1992) and further clarified by Harley et al. (2004), have been affirmed by molecular analyses (e.g., Wagstaff et al. 1998; Bendebinski et al. 2011; Godden et al. 2011; Drew & Sytsma 2012), the position of Lamiaceae within Lamiales, as well as relationships and circumscription of many of the larger Lamiaceae lineages, remain poorly understood.
Currently, seven subfamilies are recognized within Lamiaceae: Ajugoideae, Lamioideae, Nepetoideae, Prostantheroideae, Scutellarioideae, Symphorematoideae, and Viticoideae. Additionally, there are 10 genera that were not assigned to a subfamily by Harley et al. 2004.