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Thymus
vulgaris L.
Standardized Common
Name: Thyme
Other Common Names: Common Thyme, Garden
Thyme
Family: Lamiaceae (Labiatae)
Taxonomy: Thymus is
native to Eurasia, with a center of diversity in the Mediterranean region, and
includes eight sections and 215–350 species, of which several are used
commercially and most if not all have potential utility. As the species are
variable and hybridize freely even among sections, delimitation of species
boundaries is often difficult. T. vulgaris and T. zygis L.
(Spanish Thyme) are classified in Sect. Thymus, Subsect. Thymus,
which comprises about nine species of small shrubs characterized by linear,
hairy leaves with revolute margins.
Description: Shrub,
(10–)20–30(–50) cm high; branches quadrangular, slender, ascending. Leaves
opposite, short-petioled or sessile, 3–12 mm long, 0.5–3 mm broad, linear to
elliptical or ovate; base obtuse; apex more or less acute, often rounded at
tip; margins revolute; lower surface pubescent with short matted grayish hairs,
upper surface glandular-dotted; midrib conspicuous on lower surface.
Inflorescence headlike or a series of verticillasters, many-flowered,
bracteate; bracts leaflike, broader than leaves and with margins less strongly
revolute. Most flowers bisexual, some female. Calyx 3–4 mm long,
bilabiate-campanulate, (9–)10–12(–13)-nerved, green often with violet spots;
upper lip shorter, reflexed, 3-lobed; lower lip longer, pubescent, consisting
mostly of two lanceolate teeth. Corolla whitish to pale pink or pale purple,
about twice as long as calyx, tubular with weakly asymmetrical lobes; upper lip
1-lobed, emarginate; lower lip 3-lobed. Stamens 4, 2 longer, 2 shorter; may be
reduced or absent in some flowers, these flowers smaller than hermaphroditic
flowers. Style gynobasic; fruit four nutlets.
Parts
in Commerce:
Leaves and flowering tops
Identification:
Leaves
- Leaves 3–10(–12)
mm long, 0.5–3 mm broad, linear to ovate, tough in texture
- Leaf margins
revolute, not ciliate with hairs extending outward
- Lower surface of
leaf with grayish coat of hairs; upper surface with small glandular dots
- Midrib prominent
on lower surface; venation otherwise inconspicuous
- Base obtuse,
sometimes tapering to short petiole
- Apex acute to
rounded-acute
- Odor aromatic
- Taste aromatic
Flowering
tops
- Inflorescence
headlike or an interrupted spike of verticillasters
- Rachis (stem) of
inflorescence weak, usually <1 mm in diameter
- Inflorescence bracteate
and with small bracteoles subtending flowers
- Bracts
resembling leaves, often broader and with weakly revolute margins
- Calyx 3–4 mm
long, bilabiate
- Upper calyx lip
with 3 acute lobes; lower lip longer than upper, consisting of 2 narrow
pubescent teeth
- Corolla usually
6–8 mm long, about twice as long as calyx, tubular, weakly bilabiate
- Corolla pinkish
to pale purple or white, often turning pale yellow to brown when dried
- Upper corolla
lip 1-lobed, broad and rounded with small notch in center; lower lip
3-lobed
- Odor and taste
aromatic
Loose
bracts may appear to be leaves that are broader and with flatter margins than
expected; they should not be mistaken for contaminants.
Adulterants: Of the several other
economically important species of thyme, Thymus zygis (Spanish Thyme)
most closely resembles T. vulgaris and is often considered to be freely
substitutable for the dried herb. T. zygis and most other members of
Subsect. Thymus differ from T. vulgaris in that their leaf
margins are ciliate near the base. The leaves of T. zygis are small and
always narrow, under 1.2 mm broad, and sometimes have a violet midrib.
References:
Jalas J. Thymus. In: Tutin TG, Heywood VH, Burges NA, et al., eds. Flora Europaea. Vol. 3. Cambridge: Cambridge University Press; 1972:172–182.
Morales R. The history, botany and taxonomy of the
genus Thymus. In: Stahl-Biskup E, Sáez F, eds. Thyme: the Genus
Thymus. London: Taylor & Francis; 2002:1–43.
Stahl-Biskup E. 2002. Thyme as a herbal drug—pharmacopoeias
and other product characteristics. In: Stahl-Biskup E, Sáez F, eds. Thyme:
the Genus Thymus. London: Taylor & Francis; 2002:293–316. Medicinal and
Aromatic Plants—Industrial Profiles, vol. 24.
Wichtl M, ed. Herbal Drugs and Phytopharmaceuticals, 3rd English ed. Stuttgart:
medpharm Scientific Publishers and Boca Raton, FL: CRC Press; 2004:607–610.
Figure 75: a–c, Thymus vulgaris flowering top, flower and leaves; d–e, T.
zygis flowering top and leaves. |
