(Greek, hedgehog-like). Cactaceae. Sea-Urchin Cactus. South American small condensed cacti.

Stems spherical to ellipsoidal or rarely columnar: ribs prominent and usually sharp-angled: flowers usually long trumpet-shaped; ovary and tube covered with linear-lanceolate, cuspidate bracts which become longer toward the outer end of the tube, where they pass gradually into the outer petals, in their axils bearing long, silky, wavy hairs and usually a few rather rigid bristles. - This is a well-marked genus of about 18 species, although by some authors combined with Cereus. Cult, as for Echinocactus; see also Succulents.

Only a few species of Echinopsis are grown in this country, although they are more easily grown and propagated than most of the United States species of cacti. The genus is well adapted for use as window plants.

a. Ribs of stem divided into more or less evident tubercles. Pentlandii, Salm-Dyck (Echinocactus Pentlandii, Hook.). stem simple, later branching, spherical or ellipsoidal, reaching 6 in. diam.: ribs 12-15, divided between the areoles into oblique compressed tubercles: radial spines 9-12, spreading, straight or slightly curved, yellowish brown, the upper the longest and strongest, reaching 1/2-1 1/4 in.; central solitary, or seldom in pairs, porrect, curved, 1-1 1/2 in., rarely 3 in. long: flowers lateral, 2-2 1/2 in. long, yellow, orange, pink to scarlet-red: fruit spherical, green, 3/4\n. diam. Peru, Bolivia. B.M. 4124 - Probably not of this genus.

aa. Ribs of stems not divided. B. Flowers red or pink. multiplex, Zucc. stems at first rather clavate, later globose to ellipsoidal, abundantly branching, 6-12 in. diam. and the same in height, or rarely taller, light green to yellowish: ribs 12-14, straight, scarcely undulate: radial spines about 10, subulate, straight, yellow to yellowish brown, with darker tips, reaching 3/4in. length, very unequal, horizontally spreading; centrals mostly 4, of these the lowest is the longest, reaching 1 1/2 in., somewhat porrect at first, later curved and deflexed, darker colored than the others: flowers rare, lateral, 11-15 in., rose-red. S.Brazil. B.M. 3789. variety cristata, Hort. stems flat and spreading in growth, like an open fan or the flower-stalk of the common garden cockscomb: spines reduced to fine, stiff bristles. This is merely a monstrosity of the species.

Oxygona

Zucc. stems at first simple, nearly spherical or rarely clavate, becoming short columnar, reaching 1 1/2 ft. height and 1 ft, diam., gray-green, darker above: ribs 13-15, straight or wavy at the base: radial spines 5-15, horizontally spreading, very unequal, reaching 5/8in., subulate, obliquely upright; centrals 2-5, somewhat longer, straight, porrect or deflexed, dark horn-colored, with black tips: flowers commonly many together, lateral, reaching 13 in. length, pink to carmine-red, the inner petals lighter than the outer ones. S. Brazil.

Triumphans

Jacobi. This is a hybrid between E. Eyriesii and E. oxygona, with pink double flowers

bb. Flowers white.

Eyriesii, Zucc. stem simple, commonly branching later, at first somewhat depressed, later short to rather tall columnar, reaching a height of 2 ft. and a diam. of 4-6 in., dark green: ribs 11-18, straight, undulate, with sharp-angled margins: radial spines about 10, scarcely more than 1/8in long, rigid, straight, slender conical, pointed, dark brown to black; centrals 4-8, but very little different from the radials: flowers lateral, 10-15 in. long, white: fruit small, ellipsoidal, about 1 in. long. S. Brazil, Uruguay and Argentina. B.M. 3411. B.R. 1707 (as Echinocactus).

Gemmata

K. Sch. (E. turbinata, Zucc). Fig. 1377. stem simple or sometimes branching, at first low spherical or short columnar, later more top-shaped, reaching 1 ft. height by 4-6 in. diam., dark green: ribs 13-14, rarely more, straight or sometimes slightly spiral with sharp or obtuse margins, which are but little or not at all undulate; central spines appear first, about 3-6 in number, very short, stiff, black; later the radials appear, about 10-14, longer, horizontally spreading, at first yellowish brown, later horn-colored: flowers lateral or from the upper areoles, 9-10 in. long, clear white, with a pale greenish midline in the petals. S. Brazil.

Echinopsis gemmata

Fig. 1377. Echinopsis gemmata

Tubiflora

Zucc. (E. Duvalii, Hort. E. Zuccarinii, Pfeiff.). stems spherical to ellipsoidal, at first simple but later more or less branching, reaching 10 in. height by 8 in. diam., dark green: ribs 11-12, straight, with margins inconspicuously undulate: radial spines numerous, sometimes as many as 20, unequal, horizontally or obliquely spreading, yellowish white with brown tips, sometimes darker; centrals 3-4, the lowest the longest, reaching 5/8in., later deflexed: flowers lateral, about 14 in. long, white with pale green midline in the petals. S. Brazil and Uruguay. B.M. 3627.

C. H. Thompson.