Catnip is a fairly typical example of the Mint family of plants. While this plant is occasionally cultivated in residential areas, it escapes readily and is more often found in the wild. Catnip is fairly easy to identify, in part because of its distinctive aroma, which is not entirely pleasant to humans. Perhaps the most distinctive feature of Catnip is the appearance of the dense whorls of flowers on the spike-like racemes. These whorls of flowers are crowded closely together and are rather sloppy in appearance. Other members of the Mint family usually produce axillary whorls of flowers above the opposite leaves, or they produce terminal spike-like racemes that are more slender or interrupted. The flowers of Stachys spp. (Hedge Nettles), another genus in the Mint family, have an upper lip that is more similar in size to the lower lip, whereas in Catnip the upper lip of the flower is substantially smaller than the lower lip. Another common member of the Mint family, Teucrium canadense (American Germander), has an upper lip on its flowers that is even more reduced in size than Catnips., Some members of the Mint family have foliage that is coarsely hairy, or devoid of hairs, the foliage of Catnip is finely pubescent (canescent). Furthermore, the leaves of Catnip are cordate at the base, rather than wedge-shaped or rounded.
Catnip (Nepeta cataria), http://www.illinoiswildflowers.info/weeds/plants/catnip.htm (accessed January 27, 2017).