Opuntia phaeacantha  Engelm.
 

by Katie Hess, Native Plants of Arizona 2004
Common names: New Mexico prickly pear, brown spine prickly pear, Nopal pardo (Spanish), tulip prickly pear,  Densely spined prickly pear, major prickly pear, Mojave provely pear, purple-fruited prickly pear, yellow spined prickly pear (1,3,5 ).

Family:  Cactaceae   (1)
Synonymy: Opuntia camanchica O. phaeacantha var. camanchica, Opuntia mojavensis, O. phaeacanthat var. mojavensis, Opuntia angustata (Engelmann &Bigelow), Opuntia phaeacantha var. nigricans, Opuntia phaeacantha var. major (Engelmann), Opuntia superbospina, O. phaeacantha var
Etymology: Phaea come from latin phae for gray, and cantha means thorn/thistle.  (6)

Identification
Growth form: Shrub/sub-shrub perennial, (2) mature height 24’’-36 ()
Roots: Fibrous, occasionally found with tuberous roots (3). 
Stem: Stem segments obovate to nearly round, form chains, blue- green occasionally with purple tint around areoles in winter. (Betacyanin pigments) (3,4,5) Surface is glaucous. Cactus is ascending and trunk less or low and prostrate. (5)
Leaves: Elongate conical to 9mm long (4,5)
Inflorescence/flowers: Yellow sometimes shading to red basally.  It is 6-8 cm long/diameter. Stamens are yellowish or cream colored. Style is pinkish whitish long. Stigmas have 6-10 short lobes, (3,4,5)
Fruit: Fruits obovate, reddish –purple (wine-colored)  fleshy, smooth, 4-8 cm long and  2-4 cm in diameter. (3,4,5) Persist till winter. Seeds are light tan or grayish irregular discoid. (4)
Spines: 1-8 per areoles, reddish brown to dark brown or sometimes pale yellow, gray or white.  They can point in all directions. (3,4,5)
Glochids: Brown, reddish tan or yellowish brown about 1.2 cm long. (4,5) They become more numerous on older pads (3).
Areoles: Elliptical approximately 2 cm apart (3,5), become round and enlarged when older (5)
Similar species: O. phaeacantha has 10 recognized varieties in US, and another 7 in Mexico. (4)

Ecology
Life history: shrub/sub-shrub perennial. (2)
Native/introduced:  Native (2).
Photosynthetic pathway:
Phenology:  Flowers April to May (4).
Distribution: Occurs widely through southwestern United States, as far north as Nebraska, Colorado and Montana, as far west almost to the Pacific. It is also in much of northern Mexico (3,4)

Uses
Stems used medicinally, ex heated pad placed on new mother’s breast to encourage mild flow (5). Fruits used in making face paint. (5). Young stems can be eaten, as well as fruit. (4)

References

1.  Integrated Taxonomic Information System (ITIS) (http://www.itis.usda.gov).

2.  USDA, NRCS.  2002.  The PLANTS Database, Version 3.5.  (http://plants.usda.gov).  National Plant Data Center, Baton Rouge, Louisiana 70874-4490  USA.

3. Weniger, D. 1985. Cacti of the Southwest: Texas, New Mexico, Oklahoma, Arkansas and Louisiana. University of Texas Press. Austin.

4.Benson, L. 1982. The cacti of the United Staes and Canada. Stanford University Press. Stanford.

5. Anderson, E.F. 2001. The cactus Family. Timber Press. Portland, Oregon.

6. Dictionary of Botanical Terms. (http://www.winternet.com/~chuckg/dictionary.html)