General: Common Fishhook Cactus (Mammillaria tetrancistra) is a small, mound-shaped cactus with short, thin white spines that nearly cover the plant plus longer, darker, fish-hook shaped spines that stand out from the body of the plant. In early summer, red to lavender flowers emerge from the side of the stem that are nearly as large as the entire plant.

Fishhook Cactus is also the general name for the group of small, rounded cactus that mostly grow to about 3-4 inches tall by 3-inches wide (usually 2 by 2 or smaller). The stems do not have the ribs (flutes) seen in some other cactus. The plants are densely covered with relatively long, stout, spines, usually ending with a fish-hook-like bend at the tip. Some species of fishhook cactus grow in small groups, but other are solitary. Seven species of fishhook cactus occur in Nevada: one species of Mammillaria and six species of Sclerocactus.

Family: Cactus (Cactaceae).

Other Names: Fish-hook cactus, nipple cactus.

Plant Form: Short, solitary, unbranched, rounded stem that emerges from the ground.

Height: Usually 2-3 inches tall, 2 inches in diameter (to 10 inches tall and 3 inches in diameter).

Trunk: None.

Stems: Single, upright, short and cylindrical (nipple shaped).

Stem Surface: Ribbed, but inconspicuous under the radial spines.

Spines: Central: 3 to 4 per ariole, to 1 inch long, generally hooked with dark tips. Radial: many (30 to 60 per ariole), shorter than central spines, mostly white.

Glochids: Absent.

Leaves: None.

Flowers: Blooms in early summer. Flower almost as large as the plant, about 1-1/2 inches across; deep pink to lavender.

Fruit: Cylindrical, about 1/2 to 1-1/4 inches long.

Seeds: Small, brown.

Habitat: Rocky bajadas and desert peaks.

Distribution: California to Utah and Arizona, and south into northern Mexico.

Elevation: Near sea level to about 4,500 ft.

Comments: Of the seven species of Fishhook Cactus, I've only seen two around Las Vegas (and only one specimen of each).