An evergreen shrub, much branched, 6 to 12 in. high, with a woody base and slender, semi-herbaceous, greyish, downy young shoots. Leaves stalkless, 1⁄4 to 1⁄2 in. long, 1⁄16 to 1⁄8 in. wide, linear to ovate, toothless, grey downy, dotted with numerous oil-glands; margins recurved. Flowers lilac-coloured or pale purple, opening from May to July in axillary whorls, the whole forming a terminal spike 1 to 2 in. long and 1⁄2 in. wide; bracts no wider than the leaves. Corolla about 1⁄4 in. long; calyx hairy, about as long as the corolla-tube, cylindric, with three very short triangular teeth and two longer, awl-shaped ones.
Native of S. Europe from Portugal to Greece, especially in the Mediterranean region; also of Corsica and the Balearic Isles. It has been grown in Britain from ancient times chiefly as a flavouring herb and for its pleasant aromatic odour. Oil of thyme, produced from the plant by distillation, chiefly in the south of France, is used for scenting soaps and as a local external stimulant. According to Gerard, the herbalist, thyme taken internally has many virtues, some curiously diverse, such as being ‘good against winde in the belly’ and ‘profitable for such as are fearfull melancholicke and troubled in minde.’ It is scarcely employed at all in English medicine to-day.
T. × citriodorus (Pers.) Schreber T. serpyllum var. citriodorum Pers.; T. serpyllum var. citratus West. Lemon Thyme. – This old garden plant is the ‘Serpyllum citratum’ of Parkinson – ‘The wilde Tyme that smelleth like unto a Pomecitron or Lemon …’ (Paradisus). Linnaeus recorded it in his Species Plantarum (1753) as a variety of T. serpyllum under the Greek letter [gama], without naming it, but citing Serpyllum foliis citri odore of Caspar Bauhin’s Pinax (1623). Since then it has received many names, either as a species or as a variety of T. serpyllum. But it is intermediate in its characters between T. vulgaris and T. pulegioides and Ronniger’s view, adopted here, was that it is a hybrid between them.
Miller found that it did not come true from seed and insisted that it must be increased by slips or cuttings. Unfortunately, later gardeners have been less scrupulous, and the true variety has had to be reselected from stocks of seedling origin. The lemon thyme makes a spreading bush up to 1 ft or slightly more high, differing from the common garden thyme in its somewhat broader, ovate or lanceolate, more or less glabrous leaves.
T. carnosus Boiss. T. nitidus Hort., not Guss. – Related to T. vulgaris, but with fleshy leaves, wider inflorescence-bracts and whitish flowers. It is more erectly branched than the cultivated forms of T. vulgaris, almost fastigiate, to about 1 ft high. Native of southern Portugal.