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.

P. LAUROCERASUS (syn Cerasus Laurocerasus).—­Common, or Cherry Laurel.  Levant, 1629.  Although a well-known garden and park shrub, of which a description is unnecessary, the common or Cherry Laurel, when in full flower, must be ranked amongst our more ornamental shrubs.  There are several varieties all worthy of culture for the sake of their evergreen leaves and showy flower spikes.  P. Laurocerasus rotundifolia has leaves that are broader in proportion to their length than those of the common species; P. Laurocerasus caucasica is of sturdy growth, with deep green leaves, and a compact habit of growth; P. Laurocerasus colchica is the freest-flowering Laurel in cultivation, with horizontally arranged branches and pale green leaves; P. Laurocerasus latifolia, a rather tender shrub, with bold handsome foliage; and P. Laurocerasus parvifolia, of low growth, but never very satisfactory in appearance.  Three other less common forms might also be mentioned.  P. Laurocerasus angustifolia, with narrow leaves; P. Laurocerasus camelliaefolia, with thick leathery foliage; and P. Laurocerasus intermedia, halfway between P. Laurocerasus angustifolia and the common Laurel.

P. LUSITANICA (syn Cerasus lusitanica).—­Portugal Laurel.  Portugal, 1648.  A well-known shrub or small growing tree, and one of the most valuable of all our hardy evergreens.  It is of neat and compact growth, with a good supply of bright green shining foliage, and bears long spikes of pleasing creamy white perfumed flowers.  P. lusitanica myrtifolia (Myrtle-leaved Portugal Laurel) differs from the species in the smaller, longer, and narrower leaves, which are more thickly arranged, and in its more decided upright habit.  P. lusitanica variegata is hardly sufficiently constant or distinct to warrant recommendation.  P. lusitanica azorica, from the Azores, is of more robust growth than the common plant, with larger and richer green leaves, and the bark of the younger branches is of a very decided reddish tinge.

P. MAHALEB (syn Cerasus Mahaleb).—­The Mahaleb, or Perfumed Cherry.  South Europe, 1714.  This and its variegated variety P. Mahaleb variegata are very free-flowering shrubs, and of neat growth.  The variegated variety is well worthy of attention, having a clear silvery variegation, chiefly confined to the leaf margin, but in a less degree to the whole of the foliage, and imparting to it a bright, glaucous tint that is highly ornamental.  There is a partially weeping form named P. Mahaleb pendula.

P. MARITIMA.—­Beach or Sand Plum.  North America, 1800.  A prostrate, spreading shrub, that is of value for planting in poor sandy soil, and along the sea coast.  The flowers are small, but plentifully produced.