P. NANA (syns Amygdalus nana and A.  Besseriana).—­Dwarf Almond.  From Tartary, 1683.  This is of dwarf, twiggy growth, rarely more than 3 feet high, and bearing an abundance of rose-coloured flowers in early February.  From its neat, small growth, and rich profusion of flowers, this dwarf Almond may be reckoned as a most useful and desirable shrub.  Suckers are freely produced in any light free soil.

P. PADUS (syn Cerasus Padus).—­Bird Cherry or Hagberry.  An indigenous species, with oblong, doubly-serrated leaves, and terminal or axillary racemes of pure-white flowers.  It is a handsome and distinct small-growing tree, and bears exposure at high altitudes in a commendable manner.

P. PANICULATA FLORE-PLENO (syns Cerasus serrulata flore-pleno and C.  Sieboldii).—­China, 1822.  This is one of the most desirable of the small-growing and double-flowered Cherries.  It is of neat growth, with short, stout branches that are sparsely furnished with twigs, and smooth, obovate, pointed leaves, bristly serrated on the margins.  Flowers double and white at first, but afterwards tinged with pink, freely produced and of good, lasting substance.  P. paniculata Watereri is a handsome variety that most probably may be linked to the species.

P. PENNSYLVANIA.—­American Wild Red Cherry.  North America, 1773.  This is an old-fashioned garden tree, and one of the choicest, producing in May a great abundance of its tiny white flowers.

P. PERSICA FLORE-PLENO (syns Amygdalus Persica flore-pleno and Persica vulgaris), double-flowering Peach, is likewise well worthy of culture, there being white, rose, and crimson-flowering forms.

P. PUDDUM (syns P. Pseudo-cerasus and Cerasus Pseudo-cerasus).—­Bastard Cherry.  China, 1891.  There are very few more ornamental trees in cultivation in this country than the double-flowering Cherry.  It makes a charming small-growing tree, is of free growth and perfectly hardy, and one of, if not the most, floriferous of the tribe.  The flowers are individually large, pinky or purplish-white, and produced with the leaves in April.

P. SINENSIS.—­China, 1869.  A Chinese Plum of somewhat slender growth, and with the branches wreathed in small, white flowers.  It is often seen as a pot plant, but it is one of the hardiest of its family.  P. sinensis flore-pleno is a double white form, and the most ornamental for pot work.  There is also a variety with rose-coloured flowers.

P. SPINOSA.—­Sloe, or Blackthorn.  An indigenous, spiny shrub, with tiny white flowers; and P. spinosa flore-pleno has small, rosette-like flowers that are both showy and effective.

P. TOMENTOSA.—­Japan, 1872.  This is one of the most desirable of hardy shrubs, with large, white, flesh-tinted flowers produced in the first weeks of March, and in such quantities as almost to hide the branches from view.  It forms a well-rounded, dense bush of 5 feet or 6 feet high.