red when young, almost black when ripe; young branches 1/4 in. to 1/2 in. in diameter.  Leaves 1/2 in. apart, 3 in. to 6 in. long by 1 in. to 2 in. wide, oblong, pointed, with short petioles, and a small tuft of short, brown hair, with three or more reddish spines, in the axil of each.  Flowers on the ends of the young, ripened branches, clustered in the upper leaf-axils, each flower 2 in. across, and composed of a regular circle of rosy-red petals, with a cluster of whitish stamens in the centre.  They remain on the plant several weeks.  Native of New Grenada.  Probably P. grandiflora is the same as this, or a slightly different form of it.  A large specimen may be obtained in a year or two by planting it in a well-drained bed of loam, in a warm, sunny house.  It blossoms almost all summer if allowed to make strong growth.  Pretty little flowering plants may be had by taking ripened growths from an old plant, and treating them as cuttings till rooted.  In the following spring they are almost certain to produce flowers.  Plants 1 ft. high, bearing a cluster of flowers, are thus annually obtained at Kew.  Fig. 87 represents a short, stunted branch, probably from a specimen grown in a pot.  When planted out, the leaves and spine-cushions are farther apart.

[Illustration:  Fig. 87.  Pereskia bleo.]

P. zinniaeflora (Zinnia-flowered); Fig. 88.—­Stem erect, woody, branching freely, the branches bearing oval, acuminate, fleshy, wavy-edged, green leaves, with short petioles, and a pair of spines in the axil of each.  Spine-cushions on old stems crowded with stout, brown spines.  Flowers rosy-red, terminal on the ripened young shoots, and composed of a whorl of broad, overlapping petals, with a cluster of stamens in the centre, the whole measuring nearly 2 in. across.  This species is a native of Mexico; it grows and flowers freely if kept in a warm house.

[Illustration:  Fig. 88.  Pereskia zinniaeflora.]

CHAPTER XVI.

THE GENUS RHIPSALIS.

(From rhips, a willow-branch; referring to the flexible, wand-like branches of some of the kinds.)

About thirty species of Rhipsalis are known, most of them more peculiar than ornamental, although everyone is in some way interesting.  They are remarkable for the great variety in form and habit presented by the different kinds, some of them much less resembling Cactuses than other plants.  Thus, in R. Cassytha, the long, fleshy, whip-like branches and white berries are very similar to Mistletoe; R. salicornoides, with its leafless, knotty branches, resembles a Salicornia, or Marsh Samphire; another is like a Mesembryanthemum; and so on.  The flowers are usually small, and composed of numerous linear sepals and petals, arranged more or less like a star, with a cluster of thin stamens in the centre, and an erect, rayed stigma.  In the flat-jointed kinds, the flowers are developed