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|Lemon balm (Melissa officinalis)|
|Lemon balm (Melissa officinalis)|
The Lamiaceae or Labiatae (the mint or deadnettle family) are a family of flowering plants. They have traditionally been considered closely related to Verbenaceae, but in the 1990s, phylogenetic studies suggested that many genera classified in Verbenaceae belong instead in Lamiaceae. The currently accepted version of Verbenaceae may not be more closely related to Lamiaceae than some of the other families in the order Lamiales. It is not yet known which of the families in Lamiales is closest to Lamiaceae.
The family has a cosmopolitan distribution. The enlarged Lamiaceae contains about 236 genera and 6,900 to 7,200 species. The largest genera are Salvia (900), Scutellaria (360), Stachys (300), Plectranthus (300), Hyptis (280), Teucrium (250), Vitex, (250) Thymus (220), and Nepeta (200). Clerodendrum was once a genus of over 400 species, but by 2010, it had been narrowed to about 150.
The plants are frequently aromatic in all parts and include many widely used culinary herbs, such as basil, mint, rosemary, sage, savory, marjoram, oregano, hyssop, thyme, lavender, and perilla. Some are shrubs; trees, such as teak; or, rarely, vines. Many members of the family are widely cultivated, owing not only to their aromatic qualities but also their ease of cultivation: these plants are among the easiest plants to propagate by stem cuttings. Besides those grown for their edible leaves, some are grown for decorative foliage, such as coleus. Others are grown for food purposes, but seeds are utilized instead of leaves, such as with chia.
The original family name is Labiateae, so given because the flowers typically have petals fused into an upper lip and a lower lip. Although this is still considered an acceptable alternative name, most botanists now use the name "Lamiaceae" in referring to this family.
The leaves emerge oppositely, each pair at right angles to the previous one (called decussate) or whorled.
The stems are frequently square in cross section, but this is not found in all members of the family, and is sometimes found in other plant families.
The flowers are bilaterally symmetrical with 5 united petals, 5 united sepals. They are usually bisexual and verticillastrate (a flower cluster that looks like a whorl of flowers but actually consists of two crowded clusters).
The last revision of the entire family was published in 2004. It described and provided keys to 236 genera. These are marked with an asterisk in the list below. A few genera have been established or resurrected since 2004. These are marked with a plus sign. The remaining genera in the list are mostly of historical interest only and are from a source that includes such genera without explanation. Few of these are recognized in modern treatments of the family. Adelosa is a nomen dubium. No specimen exists and no one knows what Carl Ludwig Blume described as Adelosa in 1850.
The circumscription of several genera has changed since 2004. Tsoongia, Paravitex, and Viticipremna have been sunk into synonymy with Vitex. Huxleya has been sunk into Volkameria. Kalaharia, Volkameria, Ovieda, and Tetraclea have been segregated from a formerly polyphyletic Clerodendrum. Rydingia has been separated from Leucas. The remaining Leucas is paraphyletic over four other genera.
In 2004, Lamiaceae were divided into seven subfamilies with ten genera not placed in any of the subfamilies. The unplaced genera are: Tectona, Callicarpa, Hymenopyramis, Petraeovitex, Peronema, Garrettia, Cymaria, Acrymia, Holocheila, and Ombrocharis. The subfamilies are Symphorematoideae, Viticoideae, Ajugoideae, Prostantheroideae, Nepetoideae, Scutellarioideae, and Lamioideae. The subfamily Viticoideae is probably not monophyletic. Prostantheroideae and Nepetoideae are divided into tribes. These are shown in the phylogenetic tree below.
Most of the genera of Lamiaceae have never been sampled for DNA for molecular phylogenetic studies. Most of those that have been are included in the following phylogenetic tree. The phylogeny depicted below is based on seven different sources.
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