This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
A large genus of perennial herbs, for the greater part rather unattractive. Flowers axillary or terminal. Calyx tubular, 15-ribbed, 5-toothed, equal or unequal. Corolla-tube narrow, dilated and naked at the throat; upper lip straight, bifid; lower lip trifid; central lobe largest. Stamens 4, ascending under the upper lip, anther-cells diverging. Nutlets smooth. The species are estimated at upwards of 100, from the temperate and warm regions of the northern hemisphere. We have two indigenous species: N. Cataria, Catmint, and N. Glechoma, syn. Glechoma hederacea, Ground Ivy. Probably the former is not truly native, as it seems to be found only in the vicinity of ancient buildings and gardens. The Ground Ivy is a common plant in England, and one of our earliest Spring flowers. The name is of Latin origin and was applied by the ancients to some plant of this order. It is supposed to be derived from Nepete, a city in Tuscany.
1. N. Mussini. - This appears to be the correct name of the species in general cultivation under various names. It is the species employed for bedding purposes. Different varieties bear the names macrantha, longifiora, etc. It grows from 1 to 3 feet high, with oblong-cordate obtuse hoary toothed leaves, and flowers of some shade of blue according to the variety, in leafy spikes of whorls, lasting for a considerable time. It is found in various parts of Asia Minor and Siberia.