This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
Crown of Thorns. Fig. 1442. stems 3-4 ft. long, 1/2-1 in. thick, somewhat climbing, covered with stout spines about an inch long: leaves few, on the young growth, obovate to oblong-spatulate, thin, bright green, 1-2 in. long: cyathia in long-peduncled dicho-tomous cymes, near the ends of the branches, each closely subtended by 2 broadly ovate bright red bracts. Madagascar. Flowering all the year but mostly in winter. B.M. 2902. L.B.C. 18:1713. V.
Fig. 1442. Euphorbia splendens. (X 1/3)
Fig. 1443. Euphorbia neriifolia.
2, p. 74; 14, p. 16. G.C. II. 19:816 (as E. jacquiniae-flora). - Coolhouse plant. The red bracts in the green leaves on the sinuous spiny stems are very striking. It can be trained into ornamental forms. The seedlings have larger stems and leaves and double spines, a smaller one below each of the ordinary ones.
ff. Bracts not conspicuously colored. Class Grandifolle.
1443. Arborescent or shrubby: stem obtusely 5-angled; the small mammiform podaria in rows, with short, dark-colored, divergent spines: branches somewhat whorled, bearing obovate-oblong, obtuse, thick leaves, 3-5 in. long, at the summit: small sessile cymes of greenish cyathia in the upper axils. June, July. E.Indies. Gn.M. 6:196. - The large leaves persistent from autumn to spring. Cristate forms are in cultivation Fig. 1443 shows a hedge in W. Indies.
(E. grandifblia, Haw.). Arborescent: stem terete: branches obsoletely 4-5-angled; spines small: leaves terminal, obovate-cuneate, obtuse or retuse, 6-10 in. long: small cymes axillary, peduncled: caps, drupaceous. Guinea.
Low, cespitose: branches less than an inch diam.: podaria elongated, conical, in 5 spiral rows: leaves and spines small, soon deciduous. Nativity unknown. - Rare in cult, and not well known. Probably the plants grown under this name are something else.
ee. Podaria united into ribs: branches 2-13-angled: leaves usually very small or rudimentary.
f. Angles of the branches, 2 (rarely 3), the branches flattened. Class CompressAE;.
stem obtusely 5-angled, 9 ft. high or less: branches flat, except the triangular base, 1/2in. broad: spines short, slender, dark-colored. Madagascar.
ff. Angles of the branches 3 (sometimes 4), but the main stem often 5-angled. Class Trigonae.
g. Sides of branches solid green-colored.
H. Spine-shields separated by green tissue of ribs.
Shrub, 8-10 ft. high: branches erect, jointed, 1-2 in. thick, the angles repand-dentate; spine pairs about 1 in. apart; spines 1-3 lines long: leaves very small, roundish. India. See E. lactea, No. 23.
Tree, to 30 ft. high, with trunk as much as 2 ft. diam.: branches slender, 1/2-3/4 in. wide, numerous, whorled, erect-spreading, making a dense rounded head in older plants; sides of branches almost plane; angles deeply sinuate dentate; spine pairs 1/2-3/4in. apart, spines 3-5 lines long, slender, light brown to gray: leaves very small, triangular. S. Africa
hh. Spine-shields united, forming a continuous horny edge to the ribs.
Fig. 1444. Shrub or small tree: branches 3-5 in. wide, deeply jointed, the angles broadly winged, lobed and sinuate, the edge zigzag or wavy; spines large, 1-2 in. long, light colored: leaves very small, triangular ovate. S. Africa(?). - A fine plant, with the longest spines and widest wings of all. A rapid grower, the bright pale green contrasting beautifully with the rich light brown of the spines and horny margins on young plants.
Fig. 1444. Euphorbia grandicornis.
GG. Sides of branches marbled with white or yellow.
(E. havanensis, Hort., at least in part). Fig. 1445. Similar to E. antiquorum, but with a white-marbled area running through the middle of each face of the branches. E. Indies. - One of the most common succulent euphorbias in cultivation, of fine candelabra form, and making rapid growth. The euphorbias grown for hedges in Fla., W. Indies, etc., are chiefly this species, though some may be E. antiquorum. It is often confused with E. Hermentiana. Cristate forms are in the trade as E. lactea monstrosa and E. havanensis cristata, though these should perhaps be referred to E. antiquorum.
Fig. 1445. Euphorbia lactea. No. 23.
Shrub, with closely erect, scarcely jointed branches, about 2 in. thick; sides strongly concave, striped or marbled with white, especially when young, angles closely dentate; spines slender, brown, 2-3 lines long: leaves lanceolate, 1/2-2 1/4 in. long. W. Africa G.Z. 19:101. - One of the best. The true E. candelabrum, Trem., but probably not the one common in cult, under that name, is distinguished from E. Hermentiana by its rudimentary scale-like leaves
fff. Angles of the branches 4-8 (rarely 3 on some branches). Class Polygonae.
g. Spine-shields united, forming a continuous horny edge to the ribs.
H. Sides of mature branches plane or slightly convex, angles not winged, branches about 2 in. diam.
stem 4-5-angled: branches 3-5-angled, joints tapering upward from a broad base, 4-6 in. long, 2 in. or less thick, the surface with yellow U-shaped marks from center to angles; spines stout, 1/2in. long, brown to gray. Nativity (?). J.H. III. 60:99 (as E. lactea). - Frequent in cultivation, often under the name of E. lactea; also as E. marmorata and E. tessellata.
(E. virosa, and variety ccerulescens of Berger). Low, shrubby: stem 4-5-angled: branches 3-angled at base, 4-5-angled above, 2 in. thick; joints 2 in. or less long, the sides bluish glaucous; spines stout, 1/2in. long: leaves triangular, scale-like. S. Africa G.Z. 19:102. - A handsomely colored compactly branched succulent. According to N. E. Brown, E. virosa, Willd., is quite a different plant. It is probably not in cult, in Amer.