260 ARBORETUM ET FRUTICETUM BRITANNICUM. 
the attacks of insects and diseases. They almost ail require a free loamy soil, 
not overcharged with moisture, and rich rather than poor; and, while all the 
species are increased by seeds, which, for the most part, are produced freely in 
Britain, or by cuttings of the roots, almost all the varieties are best increased 
by grafting or budding; and not, as in some other orders, with equal ease by 
cuttings of the shoots, or by layers. 
With reference to landscape-gardening, all the rosaceous trees have three 
properties which deserve to be kept constantly in view by the improver of 
grounds: Ist, they never attain a large size; 2d, they attain their natural size 
and shape in a very few years, in good soil not requiring more than from 
10 to 20 years; and 3d, they sooner take the character of old trees than the 
trees of any other natural order of ligneous plants. A few exceptions may be 
taken from different orders, such as the common field maple, the common 
laburnum, &c. ; but we know of no natural order, in which, like the Rosacez, 
all the trees are low or middle-sized, and all take the character of age while 
comparatively young. Hence their value in laying out small places, where 
the object is to make a new place appear old, or a small place appear large, 
and at the same time to combine character of form with beautiful blossoms 
in spring,-and showy (Crate‘gus, Cotoneaster, and Amelénchier) or useful 
(Pyrus and Prunus) fruit in autumn. . . 
The genera are included by DeCandolle and G. Don in five tribes; and the 
following are their names and distinctions : — 
Sect. I. Amycoa‘Le& Juss. 
Sect. Char. Fruit a drupe ; the nut 2-ovuled, 1—2-seeded. Style terminal. 
Calyx deciduous. Leaves feather-nerved, undivided, serrate, with the 
lower serratures or the petioles glanded. Stipules not attached to the 
petiole. Kernel containing more or less of -hydrocyanic acid: chiefly 
fruit trees. . 
Amy’epatus Tourn. Covering of nut not fleshy; nut even, or perforated 
Young leaves folded flatwise. Flowers almost sessile, solitary or twin, 
protruded before the leaves. 
Pe'rsica Tourn. Covering of nut very fleshy; nut wrinkled. The charac- 
ters of the other parts described under Amygdalus are the same in Pérsica. 
Armenraca Tourn. Covering of nut fleshy; nut furrowed at both edges, in 
the other parts even. Young leaves with their edges rolled inwards. 
Flowers almost sessile, solitary or a few together, protruded before the 
leaves. 
Prunus Tourn. Covering of nut fleshy; nut indistinctly furrowed at the 
edges, in the other parts even. Young leaves with the edges rolled inwards. 
Flowers upon pedicels, in groups resembling umbels, and produced before 
or after the leaves. 
Cr’Rasus Juss. Nut subglobose, even, its covering fleshy. Young leaves 
folded flatwise. Flowers upon pedicels, either in groups resembling umbels, 
and produced before the leaves, or in racemes terminal to the shoots, pro- 
truded along with them. 
Sect. I]. Spirae‘e Dec. 
Sect. Char. Fruit of 5, or fewer, capsular carpels, which are distinct from 
the calyx (which is persistent in Spirze‘a, and, perhaps, in the other 
genera), and, in most cases, from each other: each contains 1—6 seeds. 
Style terminal. Low deciduous shrubs. 
Pu’rsal4 Dec. Stamens about 20, Carpels 1—2, ovate-oblong. 
Ke’rnid Dec. Stamens about 20. Carpels 5—8, distinct. 
Spires L, Stamens 10—50. Carpels 1 to several, distinct ; stipitate ; each 
includes 2—6 seeds, affixed to the inner suture. 
Sect. III. Porenti’Luez Juss. (Synon. Dryadex Vent.) 
Sect. Char. Frait an aggregation of carpels; their integuments dry or 
