The principal American Azaleas are _A. nudiflora_, _A. viscosa_, _A. nitida_, and _A. speciosa_, all of which have the corollas of their flowers funnel-shaped. Of these _A. nudiflora_ is easily known by its stamens, which project a long way beyond the corolla, and by the tube of the corolla being longer than the limb. The plant is deciduous; and the flowers, which are produced in large terminal clusters, and which are not clammy, appear before the leaves. The common English name for this plant in some parts of the country is the American Honeysuckle, and the flowers are of various shades of red, pink, white, and purple. _A. calendulacea_, which some botanists make a variety of this species, has much larger flowers, and the leaves pubescent on both surfaces, whereas, in _A. nudiflora_ the leaves are nearly smooth and green, with only a slight fringe of hairs round the margin. There are numerous varieties of _A. calendulacea_, the flowers of which are always either yellow, red, orange, or copper-coloured, and it is supposed to be the parent of the beautiful Ghent Azaleas. _A. viscosa_ has the tube of the corolla equal in length to the limb, and rather short stamens; the flowers of this species are clammy. _A. hispidum_, which is generally considered a variety of _A. viscosa_, is still more clammy, and the tube of the corolla is wider and shorter; other probable varieties are _A. nitida_, which has shining leaves, and _A. glauca_, which has glaucous ones, as in both kinds the flowers are very clammy. _A. speciosa_ has large flowers and leaves tapering at both ends. All the species of Azalea have five stamens, but some of the varieties have ten. _Rhodora canadensis_ is a little American shrub with pink flowers, which appear before the leaves, and the corolla of which is bilabiate, the upper lip being the broadest, and cut into two or three teeth, and the lower only once cut. There are ten stamens, and the capsule is five-celled and five-valved. The leaves are deciduous, and slightly pubescent beneath; and the flowers are produced in small terminal clusters. This plant, as well as all the Azaleas above described, are now included by some botanists in the genus Rhododendron. The genus Kalmia also belongs to this tribe. The flowers of this well known shrub are very curiously constructed. The corolla is salver-shaped, that is, nearly flat, and on the under side of the limb are ten protuberances, producing as many hollows on the upper side, in which lie half-buried the ten stamens. This singular construction gives the corolla that wrinkled appearance which has procured for the plant its American name of Calico flower; while, from the shape of the leaves, it is also frequently called the Mountain laurel; it is also called Sheep laurel from its being considered poisonous to those animals when they feed on it. There are several species, which differ from each other principally in the shape of their leaves and the size of their flowers.