Philbrick, Cactus and Succulent Journal (U.S.) 36(6): 163, 1964
Opuntia oricola is probably the easiest species to recognize in coastal CA. It is also the one that was called O. littoralis the most consistently (but incorrectly) until Philbrick fixed the problem by naming it O. oricola. Everything got confused when, at the same time, L Benson expanded the concept of O. littoralis to include other taxa (including O. oricola). O. oricola is nothing like O. littoralis. Plants are ascending to clearly erect, up to 10-ft tall. Cladodes are elliptic to circular up to 10-inches long by 6- to 8-inches wide. New spines are yellow and translucent. Longest glochids are on the fruits, which are nearly spherical. See the original description. O. oricola is triploid.
O. oricola resembles O. chlorotica, and perhaps they are related, but O. oricola is triploid, whereas O. chlorotica is diploid. The species forms a tall (sometimes over 6-ft tall) robust bush, usually with one or more nearly vertical trunks. The round thick pads have lots of areoles with short, often curved, yellowish to reddish spines in all of them. The fruit is round and red with lots of prominent areoles. O. oricola is a plant of the coast and lower coastal mountains from Santa Barbara south into Baja California del Norte as well as the Channel Islands. Normally, the plant is not found more than 20 miles from the coast. But it can be found in eastern parts of the Los Angeles basin.