Griffiths & Hare, New Mexico Agricultural Experiment Station Bulletin (New Mexico College of Agriculture and Mechanic Arts) 60: 47, 1906
Opuntia cacanapa occurs in Brewster County, TX and southeast to the Gulf Coast as well as in adjacent Mexico. It may also occur inland on the South Texas Plains. The pads are blue-green and glaucous. The 2-inch long spines are yellow and sometimes brown or reddish-brown at the base. O. cacanapa my reach 8 ft or more in height. The cladodes are 5- to 7(9)- inches in diameter and are suborbicular, oval, or obovate. The stigma of the yellow flowers is yellowish-green or green. The leaves are strongly recurved. Other large species (e.g., O. alta) have recurved leaves, but they don’t curl downward as strongly. See the original citation. O. cacanapa is diploid.
O. cacanapa ‘Ellisiana’ is a garden variant of O. cacanapa that has no spines or glochids, or essentially none. O. cacanapa ‘Ellisiana’ may seem different from O. cacanapa, but O. cacanapa and O. ‘Ellisiana’ share key features that demonstrate their relatedness: 1) strongly recurved leaves on cladodes and flowers, 2) pale stigmas with white styles, 3) white filaments with yellow anthers, 4) general shape and size of the fruits, 5) obovate or subcircular cladodes, and 6) identical bloom periods. O. cacanapa plants have many or few spines. Some plants seem almost devoid of spines, but they have copious glochids. In contrast, O. cacanapa ‘Ellisana’ has no spines or glochids except for a very few weak spines on the fruit.
Lack of spines is a feature of some species and not unknown. However, lack of glochids is a very unusual condition in any Opuntia.