Nepeta is a genus of about 250 species of flowering plants in the family Lamiaceae. The members of this group are known as catnip or catmint because of their effect on cats—nepeta pleasantly stimulates cats' pheromonic receptors, typically resulting in temporary euphoria. Catmints are also used in herbal medicine for their mild sedative effect on humans.
The genus is native to Europe, Asia, and Africa. It is now also common in North America. Most of the species are herbaceous perennial plants, but some are annuals. They have sturdy stems with opposite heart-shaped, green to grayish-green leaves. The flowers are white, blue, pink or lilac and occur in several clusters toward the tip of the stems. The flowers are tubular and spotted with tiny purple dots.
Nepeta species can be subshrubs, herbaceous perennials or annual herbs. They are usually aromatic. The flowers are located in verticillasters grouped on spikes; or the verticillasters are arranged in opposite cymes, racemes, or panicles. The calyx is tubular or campanulate, they are slightly curved or straight, and the limbs are often 2-lipped with five teeth. The lower lip is larger, with 3-lobes, and the middle lobe is the largest. The flowers have 4 hairless stamens that are nearly parallel, and they ascend under the upper lip of the corolla. Two stamen are longer and stamens of pistillate flowers are rudimentary. The style protrudes outside of the mouth of the flowers. The fruits are nutlets, which are oblong-ovoid, ellipsoid, ovoid, or obovoid in shape. The surfaces of the nutlets can be slightly ribbed, smooth or warty.
Oil isolated from catnip by steam distillation is a repellent against insects, in particular mosquitoes, cockroaches and termites. Research suggests that in a test tube, distilled nepetalactone, the active ingredient in catnip, repels mosquitoes ten times more effectively than DEET, the active ingredient in most insect repellents, but that it is not as effective a repellent when used on the skin. Additionally, catnip and laced-catnip products designed for use with domesticated cats are available to consumers.
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