Monographs Details: Pteridium aquilinum (L.) Kuhn
Authority: Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.

The typical variety of this species does not occur in Puerto Rico. The Puerto Rican varieties can usually be distinguished as follows:

a. Free lobes absent from the rhachis, costae, and costules; midvein on lower surface ofthe ultimate segments usually glabrous. ..

la. var, caudatum.

a. Free lobes present on the rhachis, costae, and costules, these altemating with normal divisions; midvein on lower surface of the ultimate segments usually dark-pubescent

lb, var, arachnoideum.