Xerophyte

Description

Opuntia azureaSN|35254]]SN|25100]] is a long-spined, compact, upright, prickly-pear, species with a single trunk and shiny, pale blue-green arms (usually 1-2 m tall), or branching from the base and more or less spreading. Opuntia azureaSN|25090]]SN|25100]] was described as a Mexican species and is characterized by seasonally variable joints, uniformly blue-green or purple at the areoles, that may become uniformly purple in drought or winter. The young spines are usually golden, or reddish, but almost black with age and are borne on the upper part of the cactus. The flowers are beautiful, 3 cm long, rich golden-yellow with a vivid crimson claw; aged flowers turn a pinkish-brown throughout. It produce juicy, edible red/purple fruits.

Taxonomy

Opuntia azurea is an attractive species related to Opuntia chisosensis and Opuntia macrocentraSN|25100]]SN|25090]]. The typical O. azurea is a Mexican taxon with multiple forms and geographic races that closely approaches the international border south of Big Bend National Park in Texas. The taxonomic status of this species is controversial, complex and incompletely understood and O. azurea is considered by some a synonym of the polymorphic, and geographically variable Opuntia phaeacanthaSN|25100]]SN|35254]].

Stem Segments

Joints orbicular to obovate, 10 to 15 cm. in diameter, pale bluish green, glaucous, often purple only at the areoles, if at all (rarely uniformly purple in drought or winter).

Note

The specific epithet is after the Latin adjective, azureus, "pure deep blue," in reference to the stem colours of this species.

Flowers

Intense yellow. Perianth segments c. 3 cm long, deep yellow, with crimson claw, but in age pink throughout; filaments greenish or almost white; stigma-lobes pale green.

Blooming Season

Spring ( Mar—May ).

Chromosome Number

2n = 22. O. azurea is diploid, but other ploides exist (e.g., hexaploid), and these probably represent stand-alone species.

Spines

1-3, unequal, golden, or reddish, almost black with age, the longer ones 2 to 3 cm long, diverging, more or less pointing downward.

Fruits

Dull crimson, subglobose to ovoid, spineless, truncate, juicy, edible.

Areoles

About 2 cm apart, the lower ones spineless, the upper ones with 1 to 3 rather stout spines. Glochids numerous, dark brown.