Opuntia mesacantha Raf. subsp. mesacantha

Prickly-Pear

Shrub

Perennial

Vascular

Prickly-Pear is a native perennial succulent in the Cactus family (Cactaceae). It can be found throughout most of Alabama. Prickly-Pear occurs on rock outcrops, in sandhills, on dunes, and in dry sandy soils on roadsides and in pastures. It is a perennial with a taproot. The stems are flattened and segmented into roundish cladodes (pads) that can easily detach. The stems are green and succulent with a watery sap. The stems function as the site for photosynthesis and water storage. The stems of Prickly-Pear are covered in clusters of spines that occur on modified branches known as areoles. These areoles appear as small bumps. The spines are either modified leaves or modified bud scales. Prickly-Pear produces two types of spines—long ridged spines and short hair-like spines known as glochids. The glochids are barbed and easily detached. They are practically impossible to dislodge from the skin, and any movement often forces them deeper in. Prickly-Pear flowers are large, axillary, and solitary. The flower has an inferior ovary, numerous yellow tepals, and numerous yellow stamens. The fruit is a reddish-purple berry with numerous seeds. The young stems and fruit of Prickly-Pear are edible, but care must be exercised to remove all spines. Prickly-Pear is sometimes cultivated for its showy flowers. It prefers a well-draining, sandy soil in full sun. Cultivars without spines are available.—A. Diamond

For many decades, most Alabama native Opuntia were identified as O. pusilla [=drummondii] or O. humifusa. Maclure et al (2017) found that most of the Alabama "humifusa" determinations were in fact O. mesacantha (both subsp.) or O. cespitosa. While Maclure et al did not see any true O. humifusa specimens from Alabama in their study, that taxon is to be expected be part of the flora but less common that O. mesacantha and O. cespitosa. All older herbarium specimens previously identified as O. humifusa should be reevaluated and placed accordingly.

Native

[1] Majure, L.C., W.S. Judd, P.S. Soltis, and D.E. Soltis. 2017. Taxonomic revision of the Opuntia humifusa complex (Opuntieae: Cactaceae) of the eastern United States. Phytotaxa 290 (1): 001-065. [2] Majure, L.C. 2014. Typifications and a nomenclatural change in some eastern North American Opuntia (Cactaceae). Phytoneuron 2014-106: 1–2.