The genus Thymus (/ˈtaɪməs/ TY-məs; thymes) contains about 350 species of aromatic perennial herbaceous plants and subshrubs in the family Lamiaceae.
It is native to the Old World. Several members of the genus are cultivated as culinary herbs or ornamentals, when they are also called thyme after its best-known species, Thymus vulgaris or common thyme.
The plants grow up to 40 centimetres (16 in) tall. The stems tend to be narrow or even wiry. The leaves are evergreen in most species, arranged in opposite pairs, oval, entire, and small, 4–20 millimetres (1⁄8–3⁄4 in) long, and usually aromatic. Thyme flowers are in dense terminal heads with an uneven calyx, with the upper lip three-lobed, and are yellow, white, or purple.
A considerable amount of confusion has existed in the naming of thymes. Many nurseries use common names rather than binomial names, which can lead to mix-ups. For example golden thyme, lemon thyme, and creeping thyme are all common names for more than one cultivar. Some confusion remains over the naming and taxonomy of some species, and Margaret Easter (who holds the NCCPG National Plant Collection of thymes in the UK) has compiled a list of synonyms for cultivated species and cultivars.[5]
The most common classification is that used by Jalas, in eight sections: [6]
Micantes: Iberian Peninsula, Madeira and the Azores, includes T. caespititius
Mastichina: Iberian Peninsula, includes T. mastichina
Piperella: Monotypic section confined to the vicinity of Valencia, Spain
Teucrioides: Balkan Peninsula
Pseudothymbra: Iberian Peninsula and north Africa, includes T. cephalotos, T. longiflorus and T. membranaceus
Thymus: Western Mediterranean region, includes T. camphoratus, T. carnosus, T. hyemalis, T. vulgaris and T. zygis
Hyphodromi: Throughout the Mediterranean region, includes T. cilicicus and T. comptus
Serpyllum: The largest section, throughout whole region, apart from Madeira and Azores, includes T. comosus, T. doerfleri, T. herba-barona, T. longicaulis, T. pannonicus, T. praecox, T. pulegioides, T. quinquecostatus, T. richardii, T. serpyllum, T. sibthorpii and T. thracicus