Opuntia engelmannii

Salm-Dyck ex Engelmann, Boston Journal of Natural History 6(2): 207, 1850

Isotype (O. gregoriana); Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium

See O. lindheimeri

See checklist of differences between O. lindheimeri and O. engelmannii

 

Details

Opuntia engelmannii (including O. gregoriana) is a common and large Opuntia, found from TX to far southeastern CA. It has been confused with other large Opuntia species such as O. valida or O. orbiculata. Green and Ferguson (2011) provide a longer account of “lumped and unlumped” opuntiads (Index 3). See the original descriptionO. engelmannii is hexaploid.

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O. engelmannii can be 3 to 6(8)-ft wide and up to 6-ft tall. Plants in northerly locations or at high altitudes are smaller. The pads are often 7(8) -inches across and may be up to 12-inches long. They are typically egg-shaped, obovate, oval, or sometimes circular. Cladodes are green or or sometimes barely blue-green, but are seldom dark green. Pads may even be yellow-green when stressed. Areoles generally have (1)3 to 5(6) spines that are often off-white, tan, brown, or even pale yellow. The spines typically darken towards the base to a true brown (not red-brown) or even black, and they often fade to gray with age. Spines are variable, but generally less than 2 inches long and chalky appearing. Less-spiny-than-usual O. engelmannii plants in southeast, NM and near El Paso, TX have been called O. gregoriana but are considered synonymous with O. engelmannii herein. O. lindheimeri was described as a variety, but we accept it as a species herein. O. engelmannii ranges wide and far and there may be types that might be considered varieties but which have not been validly described.

O. engelmannii and O. lindheimeri are easily distinguished. O. lindheimeri is a plant of deeper soils and more mesic conditions (central and eastern TX and east into LA), whereas O. engelmannii is a true desert plant of rocky or shallow soils (western TX and the western deserts). See the checklist of differences between O. engelmannii and O. lindheimeri.

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