Small, Manual of the Southeastern Flora 905, 1933
Original Description
What is Opuntia atrocapensis?
Opuntia atrocapensis is a poorly documented prickly pear cactus known from the sand dunes of Monroe County, FL. It resembles O. ammophila and may be synonymous with that taxon. It has been variously conflated with O. dillenii, O. zebrina, or O. austrina.
Details
O. atrocapensis forms prostrate, much-branched plants, sometimes resurgent the tips. Cladodes are obovate, elliptical, or broadly elliptical, 5-10 cm long. Usually, there is one spine per areole. The longest spines are 2-3 cm. The fruit is narrowly obovoid to 3.5 cm long and reddish-purple. There are many seeds that are 3-3.5 mm across.
Ploidy is unknown.
Other Notes
Some botanists consider that O. atrocapensis is synonymous with O. ammophila.