P. AMERICANA (syn Sorbus americana).—­American Mountain Ash.  This species, a native of the mountains of Pennsylvania and Virginia (1782), is much like our Rowan Tree in general appearance, but the bunches of berries are larger, and of a brighter red colour.

P. ANGUSTIFOLIA.—­North America, 1750.  A double-flowered crab is offered under this name, of vigorous growth, bearing delicate pink, rose-like flowers that are deliciously fragrant, and borne contemporaneously with the leaves.  The merits claimed for the shrub are perfect hardihood, great beauty of blossom and leaf, delicious fragrance, and adaptability to various soils.  The single-flowered form extends over large areas in the Atlantic States of North America.  They are very desirable, small-growing trees, and are described by Professor Sargent as being not surpassed in beauty by any of the small trees of North America.

P. BACCATA.—­Siberian Crab.  Siberia and Dahuria, 1784.  This is one of the most variable species in cultivation, and from which innumerable forms have been developed, that differ either in habit, foliage, flowers, or fruit.  The deciduous calyx would seem to be the only reliable distinguishing character.  It is a widely-distributed species, being found in North China and Japan, Siberia and the Himalayas, and has from time immemorial been cultivated by the Chinese and Japanese, so that it is not at all surprising that numbers of forms have been developed.

P. CORONARIA.—­Sweet Scented Crab.  North America, 1724.  This is a handsome species, with ovate, irregularly-toothed leaves, and pink and white fragrant flowers.  The flowers are individually large and corymbose, and are succeeded by small green fruit.

P. DOMESTICA (syn Sorbus domestica).—­True Service.  Britain.  This resembles the Mountain Ash somewhat, but the flowers are panicled, and the berries fewer, larger, and pear-shaped.  The flowers are conspicuous enough to render the tree of value in ornamental planting.

P. FLORIBUNDA (syns P. Malus floribunda and Malus microcarpa floribunda).—­China and Japan, 1818.  The Japanese Crabs are wonderfully floriferous, the branches being in most instances wreathed with flowers that are individually not very large, and rarely exceeding an inch in diameter when fully expanded.  Generally in the bud state the flowers are of a deep crimson, but this disappears as they become perfectly developed, and when a less striking tint of pinky-white is assumed.  From the St. Petersburgh gardens many very ornamental Crabs have been sent out, these differing considerably in colour of bark, habit, and tint of flowers.  They have all been referred to the above species.  P. floribunda is a worthy form, and one of the most brilliant of spring-flowering trees.  The long, slender shoots are thickly covered for almost their entire length with flowers that are rich crimson in the bud state, but paler when fully opened.  There are numerous,