Crested dog's-tail

Cynosurus cristatus, Crested dog's-tail, is a short-lived perennialgrass in the family Poaceae, characterised by a seed head that is flat on one side. It typically grows in species rich grassland. It thrives in a variety of soil types but avoids the acid and calcareous extremes of pH, and prefers well drained soils. It may be grown as anornamental plant.^{[citation needed]}

It is also known as crételle (French) and Wiesen-Kammgras(German, meaning meadow comb-grass). The Latin Cynosurus cristatus means 'addled crested or tufted'

It is perennial with a slighted tufted habit, a slender stem, 15 to 45 cm high, leafy at the base and thus suitable for grazing by sheep.

The spikelets are fertile or sterile, mixed within the same cluster. They are oblong or wedge shaped, 3–6 mm long, with 2 to 5 flowers.

The ligule is blunt. Leaves are folded in shoot.

Leaves are pointed at the tip, flat (not boat-shaped). The lower side of the leaf is smooth, glossy and keeled. The upper side is ribbed. Other grasses with glossy leaves include Lolium perenne and Poa trivialis.

Timothy-grass was unintentionally introduced to North America by early settlers, and was first described in 1711 by John Hurd from plants growing in New Hampshire. Hurd named the grass "hurd grass" but a farmer named Timothy Hanson began to promote cultivation of it as a hay about 1720, and the grass has been known by its present name since then. Timothy has now become naturalized throughout most of the US and Canada.

It is commonly grown for cattle feed and, in particular, as hay forhorses. It is relatively high in fibre, especially when cut late. It is considered a harsh, coarse grass little relished by livestock if cut earlier. It is considered part of the standard mix for grass hay and provides qualitynutrition for horses. Timothy hay is a staple food for domestic pet rabbits, guinea pigs, chinchillas, anddegus, often making up the bulk of their diet. Timothy hay is rich in long fibre and its abrasive texture helps to grind down the teeth, keeping both the teeth and jaw in good order.

The caterpillars of some Lepidoptera use it as a foodplant, e.g. the Essex Skipper (Thymelicus lineola), theMarbled White (Melanargia galathea). It also grows in roadsides and abandoned fields but generally requires nutrient-rich soils.

Its pollen is a common allergen; it has recently been used in small amounts as part of a new hay fevervaccine Grazax, which is designed to recondition the body's immune system so it no longer responds topollen.

Plants persist through the winter. Dead, straw-colored flowering stems may persist, but only for a short time, and are recognized by the distinctive spike-like inflorescence.