P. DAVIDIANA.--Abbé David's Almond. China. This is the tree to which, under the name of Amygdalus Davidiana alba, a First-class Certificate was awarded in 1892 by the Royal Horticultural Society. The typical species is a native of China, from whence it was introduced several years ago, but it is still far from common. It is the earliest of the Almonds to unfold its white flowers, for in mild winters some of them expand before the end of January; but March, about the first week, it is at its best. It is of more slender growth than the common Almond, and the flowers, which are individually smaller, are borne in great profusion along the shoots of the preceding year, so that a specimen, when in full flower, is quite one mass of bloom. There is a rosy-tinted form known as Amygdalus Davidiana rubra. P. DIVARICATA, from the Caucasus (1822), is useful on account of the pure white flowers being produced early in the year, and before the leaves. It has a graceful, easy habit of growth, and inclined to spread, and makes a neat lawn or park specimen. P. DOMESTICA, Common Garden Plum, and P. domestica insititia, Bullace Plum, are both very ornamental-flowering species, and some of the varieties are even more desirable than the parent plants. P. ILLICIFOLIA (_syn Cerasus ilicifolius_).--Holly-leaved Cherry. California. A distinct evergreen species, with thick leathery leaves, and erect racemes of small white flowers. A native of dry hilly ground along the coast from San Francisco to San Diego. Hardy in most situations, but requiring light warm soil and a dry situation. P. LAUNESIANA (_syn Cerasus Launesiana_).--Japan, 1870. This is a valuable addition to the already long list of ornamental-flowering Cherries. It flowers in the early spring, when the tree is literally enshrouded in rose-coloured flowers, and which produce a very striking effect. The tree is quite hardy, flowers well even in a young state, and will grow in any soil that suits our common wild species.