Engelmann & Bigelow, Proceedings of the American Academy of Arts and Sciences 3: 298, 1856
Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Holotype (O. basilaris brachyclada); Herbarium (O. basilaris brachyclada); Herbarium (O. basilaris brachyclada); Herbarium (O. basilaris brachyclada); Herbarium (O. basilaris longiareolata); Herbarium (O. basilaris longiareolata) Herbarium (O. basilaris longiareolata); Herbarium (O. basilaris longiareolata); Isolectotype (O. basilaris ramosa); Herbarium (O. basilaris heilii)
What is Opuntia basilaris?
Opuntia basilaris is a distinctive prickly pear cactus; it has the archetypical “beaver tail” look. The cladodes form dense clumps 15-30 cm tall and 30-100 cm across. The pads are blue-green and often wedge shaped or broadly obovate and (7)15-17(22) cm long.
Often the cladodes of this prickly pear are fan shaped, but they may be oval, obovate or even elongate-obovate. The pads of the major variety of this Opuntia (var basilaris) arise from a single point and form an approximate rosette. The areoles are slightly sunken. This prickly pear has blue-green or gray-green pads that are distinctive and that may have hints of purple, or they may be entirely purple under stress. Though spineless, there are numerous small glochids to be avoided.
Flowers are magenta and about 7-8 cm across, very showy. Fruit is dry. They style is white or pinkish-white, and the stigma is white. Filaments are red, anthers are yellow. The seeds are large and thick (subspheric?) and angular. They measure 6.5-9 × 6.5-7 mm.
Native Americans used O. basilaris as a medicinal plant (Anderson, 2001). Perhaps there was some beneficial effect to ingesting the cactus because it contains 3,4-dimethoxyphenethylamine, a compound related to dopamine and mescaline.
There are at least 5 described varieties of this Opuntia that we recognize:
Britton and Rose discuss several varieties that are not recognized here including: albiflora, coerulea, and nanna.
O. basilaris basilaris is by far the most commonly encountered variety. All varieties of this prickly pear are spineless except var treleasei. Read the original description. O. basilaris is diploid, but O. basilaris treleasii is triploid and may represent a separate taxon.
O. basilaris is a favorite in gardens because of its unique shape, pad colors, and bright flowers. Some clones from higher altitudes are cold-hardy.