Coloured scanning electron micrograph (SEM) of the underside of a leaf of common thyme (Thymus vulgaris). There is a dense covering of trichomes (hairs) of two types. The most numerous are needle-like with slightly jagged surfaces (green). Scattered amongst them are peltate glandular trichomes (red). In the background the small bright green regions are guard cells of stomata. The glandular hairs contain the essential oil that gives thyme leaves their fragrance. The oil is a mixture of phenols, terpenes and other organic molecules. The main constituent is thymol, an antioxidant. It also contains antibacterial compounds such as camphene and caryophyllene. Thyme is a useful culinary herb for a sunny garden position. Its oil has many alleged health benefits, including improving blood circulation, relieving stress, enhancing skin health, and even preventing hair loss. Magnification: x70 at 10x8.