Thymus L.
Aromatic, usually gynodioecious, perennial herbs or small shrubs, dotted with glands, often mat-forming with stems creeping or decumbent and 4-angled. Lvs entire; margins often revolute. Verticels 1-many-flowered, often densely packed in a terminal head, sometimes distinct. Bracts similar or dissimilar to lvs. Calyx tube cylindric to campanulate, straight, 10-13-nerved, hairy in throat; limb usually 2-lipped with upper lip of 3 teeth and lower of 2 small, ± subulate teeth. Corolla tube included or exserted, straight; limb 2-lipped, generally hairy outside; upper lip emarginate; lower lip 3-lobed. Stamens straight, divergent, usually exserted in ⚥ fls. Style gynobasic, its branches ± equal (at least in spp. in N.Z.). Nutlets smooth.
Key
c. 50 spp., Old World temperate regions. Naturalised spp. 2.
Hybrids are common in Thymus, even between members of different sections of the genus, and many spp. are difficult to separate. Thus, some authorities put the total number of spp. as high as 400.
