Succulent plants, with jointed branching stems, the joints flat, or cylindric, and small mostly subulate deciduous spirally arranged leaves, the areolae axillary, often spine-bearing and almost always with barbed bristles (glochides). Flowers usually lateral. Calyx-tube not prolonged beyond the ovary, its lobes numerous, spreading. Petals numerous, slightly united at the base. Stamens very numerous, arranged in several rows; filaments distinct or slightly united. Ovary cylindric, exserted; style cylindric, longer than the stamens; stigma 2-7-rayed. Berry pear-shaped, often spiny. [Named from a town in Greece.]

About 200 species, natives of America. Besides the following, some 90 or more others occur in the western and southwestern States. Type species: Cactus Opuntia L.

Joints flattened, oval, oblong, obovate or orbicular; stems prostrate or ascending.

Fruit fleshy, juicy, spineless or sparingly spiny.

Joints spineless, or with solitary stout spines.

1.

O. Opuntia.

Joints spiny (no. 2 sometimes unarmed), the spines 1 - 15 at each areola.

Spines white, gray or yellowish.

Joints 3'-5' long; longer spines 1/2'-1 1/2' long.

2.

O. humifusa.

Joints 6'-8' long; longer spines 1'-2 1/2' long.

3.

O. tortispina.

Spines reddish brown to black; j'oints 6'-8' long.

4.

O. camanchica.

Fruit dry, with spine-bearing areolae.

Joints orbicular or broadly obovate, flat.

5.

O. polyacantha.

Joints little flattened, ovoid, or subglobose.

6.

O. fragilis.

Joints cylindric, or nearly so; stem erect.

7.

O. arborescens.

4 Opuntia Tourn Mill Gard Dict Abr Ed 4 1754 1328

I. Opuntia Opúntia (L.) Coult. Eastern Prickly Pear. India

Fig. Fig. 2986

Cactus Opuntia L. Sp. Pl. 468. 1753.

O. vulgaris Mill. Gard. Dict. Ed. 8, no. 1. 1768.

O. Opuntia Coult. Contr. Nat. Herb. 3: 432. 1896.

Prostrate, or ascending, joints obovate, oval or orbicular, 2'-5' long. Leaves subulate, appressed or somewhat spreading, 2"-4" long, usually early deciduous; bristles greenish or yellowish brown; spines, when present, solitary, grayish or variegated, stout, not deflexed, 3"-1 1/2' long, often wanting; flowers yellow, sometimes with a reddish center, 2'-3' broad; petals 8-10; fruit obovoid, fleshy, edible, 1'-1 1/2' long, red.

In dry sandy soil, or on rocks, eastern Massachusetts to eastern Pennsylvania, Kentucky and northern Florida. June-Aug. Prickly-pear cactus. Devil's-tongue. Barberry.