WikiBotanicals:Sclerocactus

Sclerocactus ("hard cactus", from Greek; refers to the hard, dry fruit) is a genus of cacti. It comprises about 15 species, the exact number depending on the authority. These species are very xerophytic. They are sometimes called "fishhook cactus" or "little barrels".

Background
Usually simple but sometimes clustered, spiny cacti; ribs rather prominent, more or less undulate or tubercled; spine-clusters well developed, some of the central ones hooked, the others straight; flowers forming on the young areoles above and adjacent to the spine-cluster, subcampanulate, purplish; ovary oblong, bearing thin scattered scales, each with a tuft of short wool in its axils; fruit oblong to pyriform, nearly naked, dehiscing by a basal pore; seeds large, black, tuberculate; hilum lateral, large; embryo strongly curved; endosperm abundant.

Two species are known from the deserts of California, Utah, Colorado, Arizona, and southern Nevada, of which Echinocactus polyancistrus Engelmann and Bigelow is the type. The habit of the plants resembles somewhat that of Ferocactus, but the fruit is nearly naked and the scales bear small tufts of wool in their axils. The seeds, too, are not smooth or pitted as in Ferocactus but are tuberculate. The generic name is from the Greek, meaning hard, cruel, obstinate, and from the Greek, meaning cactus, referring to the formidable hooked spines which hold on in a most aggravating manner.

Species
S. brevihamatus (shorthook fishhook cactus) Varities:
 * S. b. tobuschii (Tobusch fishhook cactus) a federally listed endangered species. It is often treated as a species in its own right called Ancistrocactus tobuschii. This rare plant is known from about 200 to about 500 individual specimens on the eastern part of the Edwards Plateau. It occurs in the Juniperus ashei-Quercus fusiformis plant association on calcareous soils. Threats to the species include collecting and development in its habitat.

S. glaucus (Uinta Basin hookless cactus and Colorado hookless cactus) endemic to Colorado in the United States, where it is known only from the area between Grand Junction and Montrose. It is a federally listed threatened species. cylindrical in shape and measures up to 28 centimeters tall by 9 wide, though it is usually much shorter. During the dry season it may shrink so much it disappears beneath the soil surface. There are up to 12 white radial spines on each of its areoles, and several straight whitish, reddish, or black central spines pointing in various directions. The central spines may be 1 to 2 centimeters long or more. The fragrant funnel- or bell-shaped flower is up to 5 or 6 centimeters long and has pink tepals. The stamens have white or green filaments and yellow anthers. The fruit is barrel-shaped and up to 2 or 3 centimeters in length.

S. mesae-verdae

S. nyensis

S. papyracanthus (grama grass cactus, paper-spined cactus, and toumeya) This small cactus grows up to 8 centimeters tall by 2.5 wide. It is covered in so many spines they obscure the stems beneath. They are white, tan, or gray in color, papery in texture, and sometimes twisted or wavy in shape. The actual shape of the flower is an oval pedal. The flower is up to 2.5 centimeters long and have light-colored outer tepals with dark midstripes. The fruit is green and dry at maturity.

S. parviflorus

S. pubispinus

S. scheeri

S. sileri (Siler Fishhook Cactus, Sclerocactus sileri) is a plant found mostly in dry, desert areas. This plant is known to be a very small and rare form of cactus. It grows to about 25 cm tall and 12 cm wide. The cactus also shows a flower, which is noted out to be about 20mm in diameter, with yellowish petals that show venation in a purple color. Flowering often occurs in the spring season. The Central spines grow out to be about 15mm-30mm long and display a brownish-black color. The radial spines are 10mm-20mm long and display white color. These plants have not been determined on what humans can use them for.

S spinosior

S. uncinatus

S. whipplei (Engelmann and Bigelow). On the Little Colorado in Arizona. Usually single, but sometimes in small clusters, globose, 7.5 cm. in diameter or oblong and up to 15 cm. long; ribs 13 to 15, often spiraled, prominent, more or less tubercled; spines on seedlings all radials but on old plants both radials and centrals; radial spines 7 to 11, somewhat flattened, spreading or recurved, 12 to 18 mm. long, mostly white, but some black; central spines usually 4, the uppermost one flattened and straight, all or only one of the 3 lower ones hooked, usually brown or black, stouter than the radials; flowers from near the center of the plant, often abundant, short-campanulate, purplish to rose-colored, 3 to 4 cm. long; outer perianth-segments green with pale margins, broad, obtuse or acute; inner perianth-segments lavender, oblong, acuminate; tube-proper very short; filaments lavender; style reddish, puberulent throughout; fruit oblong, 1.5 cm. long, red, nearly naked; scales on the fruit small, hyaline, each bearing in its axil a small tuft of hairs; seeds 3 to 3.4 mm. long, much larger at the upper end than at the lower; hilum large, lateral on the lower half of the seed; "embryo curved, about three-fourths around a rather copious albumen." Distributed in Northern Arizona, southeastern Utah, and western Colorado.

S. wrightiae (Wright's fishhook cactus) This cactus has a spherical or cylindrical shape and a pale green color. It grows up to 11 centimeters tall by 8 wide. There are several pale radial spines and a few hooked central spines with darkened tips on each areole. The radial spines are up to 2 centimeters long and the central spines may exceed 4 centimeters. The fragrant funnel- or bell-shaped flowers are white to pink in color and up to 4 centimeters long and wide.