WikiBotanicals:Escobaria

Escobaria (pincushion cactus or foxtail cactus) is a genus of low-growing cacti that range from the southernmost parts of central and western Canada through northern Mexico, with one species in Cuba. The genus comprises about 23 species. The term "pincushion cactus" may also refer to the related Mammillaria.

Background
Globose or cylindric, usually cespitose cacti, never milky; tubercles grooved above; persisting asknobs at the base of old plants after the spines have fallen;spines both central and radial, never hooked; flowers small, regular, appearing from top 0 plant at bottom of groove of young tubercles; stamens and style included; fruit red, naked (or with one scale), indehiscent, globular to oblong, crowned by the withering perianth; seeds brown to black; aril basal or subventral, oval. The type species is Mammillaria tuberculora.

The two species of this genus known to Schumann were placed by him in the subgenus Coryphantha of Mammillaria; they are like the Coryphanthae in having grooved ﬂower-bearing tubercles, but are otherwise different, especially in the flowers, fruit, and seeds. Eight species are known from northern Mexico and southern Texas.

Species
E. albicolumnaria (column foxtail cactus)

E. alversonii (cushion foxtail cactus)

E. bella Cespitose, cylindric, 6 to 8 cm. long; tubercles nearly terete, 1.5 to 2 cm. long, the groove white-hairy, with a narrow brownish gland near center; radial spines several, whitish, 1 cm. long or less; central spines 3 to 5, brown, unequal, the largest 2 cm. long or more, ascending; flowers central, small, rotate, nearly 2 cm. broad; perianth-segments pinkish with pale margins, linear-oblong, acute, the outer ones ciliate; ﬁlaments reddish; upper part of style and stigma-lobes green.

E. chaffeyi Short-cylindric, 6 to 12 cm. long by 5 to 6 cm. in diameter, almost covered by the numerous white spines; tubercles rather short, light green, with a narrow groove above; radial spines numerous, spreading, bristly; central spines several, a little shorter than the radials and brown or black-tipped; flowers 15 mm. long, cream-colored or sometimes purplish; outer perianth-segments ciliate; inner perianth-segments oblong, obtuse, entire; style white; stigma-lobes very short, yellowish green; fruit crimson, 2 cm. long.

E. chihuahuensis Common in the mountains near Chihuahua. Plants often solitary, perhaps also cespitose, globose to short cylindric, very spiny; tubercles short, usually hidden by the spines; radial spines numerous, spreading; central spines several, longer than radials, usually brown or black in upper part; flowers small, 1 to 1.5 cm. long, purple; outer perianth-segments broad, often rounded at apex with ciliate margins; inner perianth-segments pointed. This plant should be compared with Mammillaria grusonii.

E. dasyacantha (Big Bend foxtail cactus). El Paso and eastward. Globose to short-oblong, usually 4 to 7 cm. in diameter but sometimes 20 cm. long; radial spines 20 or more, white, bristle-like; central spines about 9, stouter and longer than the radials, upper half usually reddish or brownish, often 2 cm. long; ﬂowers pinkish; perianth-segments narrowly oblong, ciliate, apiculate; stigma-lobes green; fruit clavate, scarlet, 15 to 20 mm. long; seeds black, 1 mm. in diameter, slightly flattened, pitted, with a narrow white subbasal hilum. Distributed in Western Texas, southern New Mexico, and northern Chihuahua. Varieties:
 * E. d. chaffeyi (Chaffey's foxtail cactus)
 * E. d. dasyacantha (Big Bend foxtail cactus)

E. duncanii (Duncan's foxtail cactus)

E. emskoetteriana (junior Tom Thumb cactus)

E. guadalupensis (Guadalupe Mountain foxtail cactus)

E. hesteri (Hester's foxtail cactus)

E. lloydii Plant growing in clumps and resembling a small species of Ecbinocereus; old plants bearing naked corky tubercles; radial spines about 20, spreading, slender, white; central spines several, stout, with black or with brownish tips, 2 cm. long; flowers greenish with a central stripe on outside, 2.5 cm. long; ﬁlaments, style, and stigma-lobes green; fruit red, globose to short-oblong, 6 to 12 mm. long; seeds black, pitted, globose, 1 mm. in diameter.

E. minima (Nellie cory cactus) It is a very popular species among cactus collectors. This is one reason why it is a highly endangered species in the wild today. This cactus is found only in Brewster County, Texas, in the United States, where there are three populations remaining near Marathon. The cactus is limited to one outcrop in the Marathon Uplift, where it grows in rocky novaculite soils. It was added to the endangered species list in 1979.

E. orcuttii (Orcutt's foxtail cactus)
 * E. o. koenigii
 * E. o. macraxima
 * E. o. orcuttii (Orcutt's foxtail cactus)

E. organensis (Organ Mountain foxtail cactus)

E. robbinsiorum (Cochise foxtail cactus) lives mostly buried in the ground with only its top few centimeters exposed. There is a cluster of spines on each areole, surrounded by a tuft of white woolly hairs. The spines are straight and white, often with dark tips, and measure 1 or 2 centimeters long. The flower is 1 to 3 centimeters long and has greenish yellow tepals. The fruit is bright red to orange, succulent, and under a centimeter in length. The plant grows in nearly solid bedrock with little soil or sand, in full sunlight. It can be found in dense colonies of up to 1000 individuals.

E. ruriyonii Cespitose, with numerous (sometimes 100) globose to short-oblong heads, grayish green, 3 to 5 cm. long with fibrous roots; tubercles 5 mm. long, terete in section with very narrow groove above; groove at first white-woolly, not glandular; radial spines numerous, acicular, white, 4 to 5 mm. long; central spines stouter than radials, 5 to 7, slightly spreading with brown or black tips, 6 to 8 mm. long; flowers 1.5 cm. long, pale purple; segments with a dark purple stripe down the middle and pale margins; outer perianth-segments narrow-oblong, with thin ciliate margins; inner perianth-segments narrower than the outer, with margins entire, acute; ﬁlaments purplish; style very pale; stigma-lobes 6, green; fruit scarlet, globose to short-oblong, 6 to 9 mm. long, juicy.

E. sandbergii (San Andres Mountain foxtail cactus)

E. sneedii (Sneed's pincushion cactus). Densely cespitose, sometimes with as many as 50 joints, creeping or spreading; joints cylindric up to 6 cm. long, 1 to 2 cm. in diameter; tubercles numerous, hidden under the many spines, terete, 2 to 3 mm. long, in age naked; groove narrow, hairy throughout its length; axils of tubercles not setose; spines 20 in a cluster or more, nearly white, or the larger ones brown at tip, longest one 6 mm. long, all usually appressed, but the longer ones near top, connivent; flowers small, 10 mm. long or less when dry, the outer segments long-ciliate; fruit (immature) a little longer than thick, 5 to 7 cm. long, green (?), at first juicy, naked; seeds globose, brown, nearly 1 mm. in diameter, pitted. Varieties:
 * E. s. leei (Sneed's pincushion cactus)
 * E. s. sneedii (Sneed's pincushion cactus)

E. tuberculosa (whitecolumn foxtail cactus). Mountains near El Paso and eastward. Usually growing in clumps, cylindric or becoming so, 5 to 18 cm. high, 2 to 6 cm. in diameter; tubercles more or less regularly arranged in spirals, 6 mm. long; radial spines numerous, white, sometimes as many as 30, cicular, 4 to 15 mm. long; central spines several, stouter than radials, brown to blackish or colored only at tips, one of them usually porrect; flowers 2.5 cm. in diameter when fully expanded, light pink; outer perianth-segments acute, ciliate; inner perianth-segments narrowly pointed; fruit oblong, up to 20 mm. long, red; seeds pitted, with a small ventral hilum. Distributed in Southwestern Texas, southern New Mexico, and adjacent Mexico. Flowers appear in the afternoon and last for two days at least.

E. villardii (Sacramento Mountain foxtail cactus)