(spiny Cereus). Cactaceae. Condensed globular, cylindrical or prostrate cacti of the United States and Mexico.

Stems single or cespitose, sometimes forming large clusters of 200-300 stems, distinctly ribbed, usually low-in stature, or, if elongated, sprawling or creeping, generally very spiny: flowers yellow, purplish or scarlet, with rather a short funnelshaped tube; flower-tube and ovary covered with clusters of spines; stigma-lobes always green. This genus has commonly been merged into Cereus, although it seems to be quite distinct.

Most of the species of Echinocereus are unsuited for greenhouse purposes, for when brought under glass they survive only for a few years. The very large flowers of some species make them very attractive while in bloom.

a. stems covered with long weak bristles or hairs, and resembling a small plant of Cephalocereus senilis.

1. De Laetii, Gurke

Low and cespitose, 6-10in. high: ribs 17-20: radial spines numerous; central spines 4 or 5, intermixed with long, hair-like bristles entirely hiding the plant: flowers small, rose-colored. Mex. - This species has been secured in great quantities by European dealers. It closely simulates a small Cephalocereus senilis, but has very different flowers and fruit

aa. stems variously covered with spines, but not like the above (Nos. 2-27).

b. The stems weak and trailing, at least becoming prostrate.

c. Ribs nearly continuous.

2. Scheeri, Lem

(Cereus Scheeri, Salm-Dyck). Branching freely from the base of the stem and forming dense clusters: branches upright or ascending, about 8 in. long by 1 in. diam., slightly tapering toward the apex, dark green: ribs 8-9, straight or sometimes inclined to spiral, separated above by sharp grooves which become flattened toward the base, low arched: areoles little more than 1/4in. apart, round, yellowish white: radial spines 7-9, spreading, needle-like, the under pair the longest, about 1/4-3/8in. long, white with yellowish bases; centrals 3, the lower the longest, about 3/8in., red with brown bases; later all the spines become gray: flowers red, from the upper part of the stem, about 5 in. long; ovary and tube bracteate and furnished with abundance of wool and spines. Mex.

cc. Ribs divided into tubercles.

d. Central spines, when present, short: flowering areoles bearing cobwebby wool.

3. Procumbens, Lem

(Cereus procumbens, Engelm.). Branching from the lower part of the stem and so forming clusters: branches procumbent or ascending, angled, at the base tapering into cylindrical, 1 1/2-5 in. long by 1/2-3/4 in. diam.: ribs mostly 5, rarely 4, straight or spiral, on the upper portion of the branch almost divided into tubercles: areoles 1/4-1/2in- apart, round, sparingly white curly-woolly, soon naked: radial spines 4-6, subulate, stiff, straight, sharp, in young growth brownish, then white, at the base often yellowish and the tip brownish, horizontally spreading, the upper the longest, reaching 1/4 in. length; central solitary or absent on the lower areoles, somewhat stronger, 3/8-5/8 in. long, darker: flowers lateral, from just below the crown, 3-4 in long, carmine-red to violet, with white or yellowish throat: fruit ellipsoidal, green, 5/8in. long. Mex.

dd. Central spines slender: flowering areoles with short wool. e. Length of central spine 3/4in.

4. Berlandieri, Lem

(Cereus Berlandieri, Engelm.). stems prostrate, richly branching, forming dense clusters, the branches upright or ascending, 2-3 in. long or longer, by 1/2-3/4 in. diam., light or dark green, and in young growth often purplish: ribs 5-6, broken up into as many straight or spiral rows of tubercles; tubercles conical, pointed: areoles 3/8-5/8 in. apart, round, white-woolly, soon naked: radial spines 6-8, stiff bristle-form, thin, horizontally spreading, white, about 3/8in. long, the upper one sometimes light brown and somewhat stronger; central solitary, yellowish brown, sometimes reaching 3/4in. length: flowers from the upper lateral areoles, 2-3 in. long, red to light pink: fruit ovoid, green, bristly. S. Texas and N. Mex.

ee. Length of central spine 1 in. or more.

5. Blankii, Palmer

(Cereus Blankii, Poselg.). Branching freely from the base and thus forming clusters: stems columnar, tapering above, about 6 in. long by 1 in. diam., dark green: ribs 5-6 (rarely 7), straight, almost divided into tubercles: areoles about 3/8in. apart, round, white curly-woolly, later naked: radial spines mostly 8, horizontally spreading, the under pair the longest, reaching about 3/8in. length, all stiff, straight, thin, white or the upper ones carmine-red when young, later reddish brown; central solitary, porrect, later deflexed, 1-1 1/4 in. long, white or brownish, black when young: flowers from near the crown, 2 1/2-3 in. long, purple-red to violet. Mex. R.H. 1865:90.

bb. The stems usually short and stout, usually erect.

c. Flowers rather small, scarlet.

d. Ribs 5-7.

E. Spines terete.

6. Paucispinus, Rumpl

(Cereus paucispinus, Engelm.). Clustered in irregular bunches: stems cylindrical to ovoid, 4-7 in. high by l 3/4-3 in. diam.: ribs 5-7, undulate: areoles 3/8-5/8in. apart, round, white-woolly, later naked: radial spines 3-6, spreading, subulate, straight or curved, round, bulbose at the base, the lowest one longest, reaching 3/4in., light-colored, the upper ones reaching to about 1/2in., reddish or brownish; central solitary or none, reaching about 1 1/2 in. length, somewhat angled, brown-black, porrect or upright; later all the spines blackish: flowers 2 in. or more long, dark scarlet to yellowish. Texas and Colo.

Variety gonacanthus, K. Sch. (E. gonacanthus, Lem. Cereus gonacanthus, Engelm. & Bigel.). Radial spines 8, very large, angled and sometimes twisted, the upper strongest, reaching nearly 3 in. length, light or dark yellow with brown tips; central always present, deeply grooved, often flattened, 3 in. or more long. Colo.

ee. Spines angled.