C. CRUS-GALLI.--Cockspur Thorn. North America, 1691. This has large
and showy white flowers that are succeeded by deep red berries. It is
readily distinguished by the long, curved spines with which the whole
tree is beset. Of this species there are numerous worthy forms,
including C. Crus-galli Carrierii, which opens at first white, and
then turns a showy flesh colour; C. Crus-galli Layi, C. Crus-galli
splendens, C. Crus-galli prunifolia, C. Crus-galli pyracanthifolia, and
C. Crus-galli salicifolia, all forms of great beauty--whether for their
foliage, or beautiful and usually plentifully-produced flowers.

C. DOUGLASII.--North America, 1830. This is peculiar in having dark
purple or almost black fruit. It is of stout growth, often reaching to
20 feet in height, and belongs to the early-flowering section.

C. NIGRA (_syn C. Celsiana_).--A tree 20 feet high, with stout branches,
and downy, spineless shoots. Leaves large, ovate-acute, deeply incised,
glossy green above and downy beneath. Flowers large and fragrant, pure
white, and produced in close heads in June. Fruit large, oval, downy,
and yellow when fully ripe. A native of Sicily, and known under the
names of C. incisa and C. Leeana. This species must not be confused
with a variety of our common Thorn bearing a similar name.

C. OXYACANTHA.--Common Hawthorn. This is, perhaps, the most ornamental
species in cultivation, and certainly the commonest. The common wild
species needs no description, the fragrant flowers varying in colour
from pure white to pink, being produced in the richest profusion. Under
cultivation, however, it has produced some very distinct and desirable
forms, far superior to the parent, including amongst others those with
double-white, pink, and scarlet flowers.