## 3 Taxonomy and Essential Oil Production of Thyme  
### Taxonomy of Thyme  
The _Thymus_ genus, consisting of around 250 taxa, includes 214 species and 36 subspecies [11]. The _Thymus_ genus is subdivided into eight sections based on geographical distribution and morphological characteristics. The Micantes section encompasses the North African woody species _T. ritararum_, _T. satureioides_, and _T. caespititius_. Morphologically, they are erect plants with flat, globous, long oblong-obovate leaves and spiciform inflorescence [12; 13]. \(\alpha\)-Terpineol is considered a major active component in _T. caespititius_ according to [PERSON] et al. [14], [PERSON] et al. [15], and [PERSON] et al. [16]. High variability in the essential oil composition of _T. ritararum_ in Morocco has been observed: [PERSON] et al. [17] revealed the dominance of Borneol as a major component, while [PERSON] et al. [18] indicate the dominance of \(\gamma\)-terpinene and p-cymene. Endemic to the Iberian Peninsula, the Mastichina section includes _T. mastichina_ subsp. _donyanae_, which are characterized generally by a high amount of 1,8-cineole, while the _T. albicans_ species show linalool as a major compound in its essential oil in addition to 1,8-cineole. Morphologically, they show capituliform inflorescence with holotrichous stems and flat, lanceolate-to-obovate leaves [13; 19; 20; 21]. The _Piperella_ section represents a unique species: _T. piperella_, endemic to Valencia and its surrounding areas in Spain. It has similar leaves and stem morphology to the Mastichina section species, but it has a verticillaster inflorescence. p-cymene and carvacrol are considered the major active constituents in this species [13; 22; 23]. The _Teucrioides_ section, originating from the Balkan Peninsula, is characterized by revolute, ovate, or triangular-ovate leaves and a verticillaster inflorescence. It comprises three different species: _T. teucrioides_, _T. hartvigi_, and _T. leucospermus_[13]. The three species show p-cymene as one of the main constituents within a population collected from Greece and Albania, as reported by [PERSON] et al. [24]. The Pseudothymbra section occurs in the Iberian Peninsula and North Africa. Morphologically, they are erect plants with linear revolute leaves and a capituliform inflorescence. It includes nine species: _T. lotocephalus_, _T. villosus_, _T. longiflora_, _T. membranacaeus_, _T. mnorderi_, _T. munbyanus_, _T. bleicherianus_, _T. funkii_, and _T. antennae_. All these species show a distinguishable number of active compounds. _T. munbyanus_ subsp. _ciliates_ from Algeria show carvacrol as a main constituent in its essential oil [13; 25; 26]. The _Thymus_ section occurs in the Western Mediterranean region, and the plants are erect or radicant with revolute leaves and spiciform or globose infloresences. It includes the most important species in thyme: _T. vulgaris_, _T. zygis_, and _T. willdenowii_[13]. _T. vulgaris_, commonly known as garden thyme, is a bushy, evergreen subshrub with small, highly aromatic gray-green leaves and clusters of purple or pink flowers. Several chemotypes are observed in this species, but generally thymol is considered the main constituent in the essential oil [27; 28; 29; 30]. The Hyphdromi section consists of plants that are subtended and rooting with revolute or flat leaves and a capituliform inflorescence. The section encompasses the entire Mediterranean region and includes 60 species [13]. _T. algeriensis_ is one of the popular species in this section with high chemical polymorphism; in Tunisia, it shows 1,8-cineole and camphor as major compounds [31], while in Algeria, in the same location but at different altitudes, _T. algeriensis_ indicates a different chemical profile: thymol type and terpinyl acetate type [32]. The Serpyllum section includes around 120 species and occurs within the genus area. Morphologically, the plants are woody, with leaves ciliated at the base and a spiciform inflorescence. The well-known wild thyme or _T.