7. Sepium, Dc

(C.Roezlii,Haage.) Upright, columnar, about 3 in. diam.: ribs 9, separated by sharp, somewhat serpentine grooves, obtuse, above the areoles, 2 radiating, slightly curved grooves form a letter V: areoles 1/2-3/4in- apart, comparatively large, slightly sunken, yellowish, later gray: radial spines 9-12, radiate, nearly 1/2in. long, straight, subulate, tolerably sharp, slightly thickened at the base, clear brown, with darker stripes; central solitary, reaching 1 1/2 in. long, straight, porrect, later somewhat deflexed, clear brown; later all the spines become gray. Andes of Ecuador. - Near Borzicactus; needs further critical study.

8. Tetracanthus, Labour

Upright, arborescent or bushy, freely branching, young branches leaf-green, later gray-green: ribs 8-9, low, arched: areoles medium-sized, slightly sunken, about 1/2in. apart, white to gray: radials 5, later 7, radiate, about 3/8in. long, straight, subulate, stout, white, with brown tips and bases, later ashy gray; centrals 1-3, under one largest and porrect, when young yellow and translucent, later gray: flowers resemble those . of C. tortuosus. Bolivia. - This species should doubtless be referred to Eriocereus.

9. Hankeanus, Web

Upright, robust, not branching (so far as known), young growth bright green, later dark green, about 2 in. diam.: ribs 4-5, compressed, about 1 1/4 in. high, conspicuously crenate, with an S-form line passing from each areole toward the center of the stem: areoles, 3/8-1 in. apart, horizontally elliptical to heart-shaped, brown, becoming gray below and yellow above: radial spines 3, needle-like, stout, sharp-pointed, about 3/8in. long, amber-colored when young, turning to brown; central solitary, straight, porrect, 5/8in. long, stronger than the radials, horn-colored; later all the spines become gray: flowers 4-5 in. long, white. S. Amer.

bb. New growth blue, white- or gray-pruinose.

c. Ribs of stem comparatively broad and low: stem more or less triangular in cross-section.

10. Macrogdnus. Otto

Arborescent, sparsely branching, reaching a height of 20 ft. (in cultivation, 6 ft. high by 3-5 in. diam.), branches columnar: ribs mostly 7, seldom 8-9, thick, slightly undulate, obtuse and with convex faces, about 1 in. high, bluish green, frequently having a depressed line near the areole: areoles about 1/2in. apart, large, gray: radial spines 6-9, radiate or spreading, strong, subulate, 3/4in. long, horn-color, later black; central spines 1-3, somewhat stronger and longer than the radials, more or less conspicuously porrect: flowers from the lateral areoles near the end of the branches, 2 1/2-3 in. long, tolerably fleshy, white: fruit depressed-globose, 2 in. diam. by little more than 1 in. long. Brazil.

cc. Ribs of stem strongly compressed laterally.

11. Peruvianus, Haw. (C. Monoclbnos, Dc)

Hedge Cactus. Fig. 884. Tall, 30-50 ft.,branching freely toward the base, columnar, 4-8 in. diam., new growth dark green and glaucous, becoming a dull green with age, and, in old stems becoming corky: ribs 5-8, compressed: areoles 1/2-1 in. apart, in new growth covered with conspicuous, curly brown wool, becoming gray: radial spines about 6-7, about 3/8-1/2in. long; central solitary, reaching a length of 2 1/2 in.; the number of spines increases with age to as many as 20, all are rigid, brown: flowers abundant, from the lower part of the stem, white, nocturnal, 6-7 in. long by 5 in. diam. S. Amer. G.C. III. 24:175 (variety monstrosus).

Cereus peruvianus. A flower that is just closing; from a plant flowered in Washington, D. C, in 1904. (X 3/5)

Fig. 884. Cereus peruvianus. A flower that is just closing; from a plant flowered in Washington, D. C, in 1904. (X 3/5) ccc. Ribs of stem 3-6.

Variety Alacriportanus, K. Schum. (C. Alacriportanus, Mart.). Of somewhat weaker growth, low, and less conspicuously pruinose in the new growth, which is consequently nearly clear green. S. Brazil.

12. Jamacaru, Salm-Dyck (C. Vdlidus, Haw.)

stems upright, robust, rigid, 12-16 ft. high by as much as 6 in. diam.; young growth azure-blue, turning dark green with age, glaucous: ribs 4-6, thin, compressed, crenate: radial spines 5-7, stiff, needle-like, clear yellow with brown points, or brown and finally black, about 1/2-3/4 in. long; centrals 2-4, somewhat stronger, porrect, 3/4-3 in. long: flowers large, 10 in. long by 8 in. diam., white, nocturnal. Brazil, Venezuela.

13. Chalybaeus, Otto

stems upright, branching above, arborescent, azure-blue and pruinose, later dark green, 1 1/2-4 in. diam.: ribs 6, in young growth very much compressed, later depressed till the stem is nearly cylindrical: areoles about 3/8in. apart, dark gray-brown: radial spines mostly 7, about 1/2in. long; centrals 3-4, similar but somewhat stronger and a little longer; all the spines are pointed, stiff, when young are black, later brown to gray with black tips, bulbose at the base: flowers very similar to those of C. caerulescens. Argentina.

aa. stems erect, less than 2 in. diam.

b. Ribs of stem 10 or more.

14. Isogonus, K. Schum

stem upright, columnar, about 1-1 1/4 in. diam., in young growth light green to yellow-green, later darker: ribs 15-16: areoles approximate, white, turning gray: radial spines as many as 20, spreading, at first clear or dark yellow, becoming white, and finally gray, bristle form, flexible, about 3/8in. long; centrals 6-8; two of these are somewhat stronger and stiffer, about 3/4in. long, one directed upward and one downward, yellowish brown to dark honey-color; later gray, as in the radials. S. Amer.

15. Splendens, Salm-Dyck

Columnar, slender, short, rigid, more or less branching from the base, reaching a height of about 2 ft. and about 1-1 1/2 in. diam., light to yellowish green: ribs about 10-12, rounded: areoles prominent, about 1/4in. apart, tawny, becoming white, tomentose: radial spines 8-12, radiating, yellow and light brown, becoming gray; centrals 1-3, scarcely larger than the radial, yellowish to white; all the spines slender, bristle form, about 1/4-3/4in. long. --C. Cavendishii has been referred to this species, but with some question.

bb. Ribs of stem 3-10.