This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Small trees or herbs with stout succulent jointed stems and alternate palmately-lobed dentate leaves on long petioles, bearing a saucer-shaped gland at the junction of the petiole and blade. Flowers monoecious, in terminal spikes. Perianth 3- to 5-parted. Male flowers having numerous stamens in separated bundles. Fruit capsular, prickly, 3-celled, 3-seeded. Seeds oval-oblong, having a spongy excrescence at one end, mottled grey and brown. The species are natives of India and Africa, though they are now widely dispersed in warm countries. The name is the Latin ricinus, a tick, from the resemblance of the seeds to that insect.
1. R. communis. Palma-Christi, Castor-oil Plant. - Though perennial, and attaining the dimensions of a small tree in warm climates, this is treated as an annual with us. As such it grows from 4 to 6 feet or more high, bearing large handsome peltate palmately-lobed leaves. There are several varieties, differing in the colour of the stems, leaves, and flowers. R. c. major is a tall variety 6 to 8 feet high with glaucous fistular stems slightly tinged with purple, and very large acutely lobed leaves. R. c. minor is about half the stature of . the last, with similar but smaller foliage. R. c. sanguineus is a handsome tall variety with brownish red stems, petioles, and flowers. The immense leaves are otherwise green, not glaucous.
R. Africanus is a distinct species with a branching head and much smaller usually 5-lobed leaves, and 6 distinct stigmas instead of 3 forked ones.
These are very showy and handsome foliage plants either singly or in groups.