Xerophyte

Seeds

White, tan to grey, flat, warped, oblong to subcircular, and about 3-7 mm long, 2-4 mm wide, acute on the margin; girdle protruding 1-2 mm. The number of seeds varies from none to more than 70 per fruit. The most fruit is produced on stem branches that are 6 to 8 years old.

Description

The plains prickly pear, Opuntia polyacanthaSN|31216]]SN|31216]] is a low shrubby spreading perennial plant with many branches, up to 10-20 cm (-40) centimetres tall, usually forming small clumps or mats of pads which may be 2–3 metres wide. . Mats up to 3.7 m in width and 9.15 m long were observed in the Great Plains. Prickly pear plants usually live less than 20 years, but vegetative propagation can ensure a very long life span for the clonal colony.Roots. Fibrous, shallow, laterally extensive that takes advantage of rainfall as scant as 2.5 mm.

Flowers

Small, yellow to magenta, 2.5 to 6 cm long, including the ovary, 4.5-8 cmin diameter; sepals tinged with red; petals lemon-yellow, orange pink or magenta; filaments white, yellow, or red to magenta (flowers may superficially appear bicolored), anthers yellow; style white to pale pink stigma lobes green.

Blooming Season

Late spring to early summer, for 3-4 weeck. Individual flowers open from 7-11 hours per day.

Taxonomic Notes

Many varieties of O polyacantha have been described but usually only these 5 are recognized. var. polyacantha, var. arenaria, var. erinacea, var. hystricina, and var. nicholii (Parfitt 1991). Populations of Opuntia polyacanthaSN|31216]]SN|31216]] with spines few or absent (especially var. hystricina) were the basis for several names including O. juniperina, O. utahensis, and O. rhodantha.

Spines

Numerous (0-)6-10(-18) mostly or only on the distal areoles of stem segment, only slightly barbed, stout or thin, straight or curling downward or bent backward, and any of a variety of colours, 0.4 to 18.5 centimetres in length, those from the sides mostly short, appressed, but often 1 or 2 of these elongated and like those from the upper and marginal areoles. Spines of 1 or 2 kinds; if 1 kind

Stem

± prostrate branches with stems segments not easily detached, succulent, flattened, low tuberculate, not very thick less than 1 cm thick, glabrous, oval or orbicular, 4-18(-27) centimetres wide, (2-)3.5-12(18) cm wide,, but usually less than 10 cm in diameter, generally light green or blue-green.

Fruits

Dry at maturity, oblong, to cylindrical, tan to brown, 15-45 mm long, 12-25 mm wide, areoles 10-33, each or only distal areoles bearing small clusters of white, acicular barbed spines. Fruits develop on stem lobes. Fruits ripen approximately 2-1/2 months after flowering.