R. salicornoides (Glasswort-like); Bot.  Mag. 2461.—­Stem woody when old, brown, jointed like hens’ toes, not quite as thick as a goose-quill.  Branches in clusters; joints 1/2 in. to 1 in. long, the lower half much thinner than the upper, so that the joints look like a number of superposed, miniature clubs.  Flowers pretty, on the ends of the terminal joints, yellow, becoming red with age.  An erect plant, 3 ft. or more high, introduced from Brazil in 1830.  The joints are clustered on the upper part of the stem.  When in flower in spring this is an attractive and very remarkable-looking plant.  It thrives best in stove temperature.

R. s. stricta (straight).—­This variety has the joints all pointing upwards, and is much more compact than the type.

R. sarmentacea (runner-stemmed); Fig. 90.—­A creeping, prostrate plant, with round stems as thick as a goose-quill, and attaching themselves to tree-trunks or other bodies by means of numerous adventitious roots, which spring from the under side of the stems.  Surface of stem furrowed, and covered with numerous small clusters of short, hair-like, whitish spines.  Flowers 1 in. across, springing from the sides of the stems, with pointed, creamy-white petals; stamens spreading; stigma erect, four-lobed.  Fruit small, currant-like.  This is a pretty little species, introduced from Brazil in 1858; it is, however, a very slow grower, plants ten years old being only a few inches in diameter.  It should be grown in stove temperature, in a basket of peat fibre, or, better still, on a piece of soft fern-stem.  It is always found on the branches or trunks of trees when growing wild.

[Illustration:  Fig. 90.  Rhipsalis sarmentacea.]

R. Swartziana (Swartz’s).—­Older stems three-angled, young ones flattened, jointed; joints 2 in. broad, stiff with deep notches.  Flowers in the notches, small, white, produced in June.  This species is a native of Jamaica, and was introduced in 1810.  A stiff, ungraceful plant, about 2 ft. high, very similar in its branches to a Phyllocactus.  This species requires the temperature of a stove.

R. trigona (triangular).—­Habit straggling; branches usually in forks, 1/4 in. in diameter, three-angled; angles wavy or slightly notched, grey-green.  Flowers small, produced in spring in the notches of the angles, white.  Fruit a white berry.  A thin, Brazilian plant, not unlike a Lepismium, but without the silky hairs in the notches of the angles.  This species also requires to be grown in stove temperature.

CHAPTER XVII.

TEMPERATURES.

To enable growers to make a selection of species according to the accommodation that can be afforded for Cactuses, all that are described in this book are here classified in three groups:  (1) Species which thrive in a cool-house or frame; (2) Species which can only be successfully grown in a warm house or stove; and (3) Species which are hardy in the more favoured portions of the United Kingdom.