Pellaea ovata is a widespread species, sexual diploid in Texas and northeastern Mexico but an apogamous triploid in northwestern Mexico, south to northern Argentina, and on Hispaniola. The type belongs to the southern, apogamous triploid form. Although these two forms have been discussed repeatedly in the literature, morphological distinctions between them have been overlooked and they have not been recognized taxonomically. However, they are distinct. Pellaea ovata s.s. has puberulent rachides and costae; pinnae usually 2-pinnate with a well-defined main axis and pinnules borne singly; fertile pinnules ovate, cordate basally and rounded apically. The sexual diploid form has rachides and costae glabrous; pinnae pseudo-dichotomously branched and pinnules usually paired; fertile pinnules narrowly rounded-trapeziform, obliquely truncate to cordate basally and truncate apically. Riddell named the sexual diploid form Pteris zygophylla, from which I give it the new combination Pellaea zygophylla.

This dataset is a list of specimens and photographic observations consulted in preparation of the manuscript. The original specimen and observation data was taken from the following data portals: PteridoPortal (pteridoportal.org), IBData (ibdata.ib.unam.mx), SEINet (swbiodiversity.org), CCH2 (cch2.org), and iNaturalist (inaturalist.org). In addition to basic accession information to allow these specimens and observations to be unambiguously identified, the dataset includes latitude and longitude coordinates. These coordinates are those provided by the data portal or on the specimen label in most cases. Where coordinates were not provided, I have included coordinates based based on the written locality description for most specimens. These coordinates, and my identifications of specimens, are the only data unique to this dataset at present, the remainder being available through the data portals listed above.

The unique portion of the dataset, as described above, is my work and in the public domain. The remainder is the work of others, and subject to any restrictions placed on it by the people and institutions who have made it available through the various online data portals.