Xerophyte

Seeds

Flattened, tan coloured, 3,5-4,5 mm in diameter, 1,5-1,9 mm thick.

Description

The Purple Prickly Pear (Opuntia macrocentraSN|25090]]SN|25090]]) is a ground-hugging to nearly upright branched shrubs 60-120 cm tall, up to 3 m wide, usually 4-10 joints high; rarely with distinct trunks. The red-tinged succulent pads and very long spines (macrocentra means long spine) easily distinguish it from the many other species of prickly pear. The purple tinge is greatest around the areoles and on the edges, although the entire plant may be purple in winter.

Stem Segments

Flat, orbicular to oblong or obovate, often wider than long, 10-20 cm broad, smooth, dark green to glaucous blue-green turning a maroon purple during the winter. The purple tinge is due to betalain pigment (presumably one particular compound, betacyanin) most evident when the plants are stressed by cold or drought.

Flowers

5-10 cm long, 6-7 cm in diameter, yellow with brilliant red throat often not opening fully, and in some plants the red pigment extends like a "mid-stripe" on the tepals (rare in Opuntia). Filaments 15 mm long, pale green and cream-coloured at the tips. Anthers yellow. The Style is 17-20 mm long with about 6 stigma lobes cream-coloured or pale green. Pericarpel 2,5-3 cm long, with few areoles on the upper half with brown glochids.

Blooming Season

Spring-summer, flowers usually last only one day, opens in the middle of the morning and close at night.

Chromosome Number

2n = 22-44 both diploid and tetraploid. Diploid and tetraploid plants of Opuntia macrocentraSN|25090]]SN|25090]] are so similar that it not possible to accurately predict ploidy levels from morphology alone.

Spines

Most commonly 1-3(-4), produced in areoles only on the upper margin of the pad, usually 3 to 7 cm long acicular or slightly flattened, straight, projecting often notably directed upward, whit the lowermost ones (occasionally up to 12 or more cm long) dark black to reddish brown, with whitish or yellowish tips. On immature stems there are fewer and shorter spines. Spineless or near spineless forms of Opuntia macrocentraSN|25090]]SN|25090]] are at least occasional. In some plants the spines may be white for most of their length (see "var. castetteri"), but usually with a black or reddish base.

Fruits

Ovoid, succulent and juicy at maturity with few areoles, 2,5-4 cm long, purple to pinkish red, edible maturing in summer-autumn. Each fruit has between 12-16 areoles. The umbilicus is deeply concave and the inner pulp and juices are light purple to clear in colour.

Areoles

2-2,5 cm apart, arranged in diagonal rows on the midstem segment, with abundant tan to reddish brown glochids, and a pile of gray to tan hairs especially in the upper areoles.