Pteridium esculentum var. harpianum Schwartsb. & A. Yanez

5.1. Pteridium esculentum var. harpianum Schwartsb. & A.Yañez, Phytotaxa 333(1): 36 (2018).Fig. 3h Plants terrestrial. Stem long-creeping, hair pale brown. Fronds approximately 154–178 cm long, monomorphic, 4-pinnate-pinnatifid, pendent; petiole approximately 96– 47.5 cm long, paleaceous, adaxially sulcate, glabrous; rachis paleaceous, adaxially sulcate, glabrous; laminae approximately 58–130.5 cm long, lanceolate, apex gradually narrowed; pinnae approximately 17 pairs; ultimate segments coriaceous, with hairs on the costae abaxially, and farinaceous appearance between the veins, distal segments simple, linear, up to 2.5 cm long; veins free. Sori linear, marginal; pseudoindusia linear, glabrous. Examined material: Barreiras do PiauÍ, PNNRP, Brejo do Curicaca, 10°00’26’’S, 45°35’52’’W, 446 m, 21.IV.2022, P. H. C. Aguiar et al. 46 (CCAA); cabeceira do Curicaca, 10°00’25’’S, 45°35’50’’W, 457 m, 16.XII.2022, P. H. Castro-Aguiar et al. 243 (CCAA). Pteridium esculentum var. harpianum is a South American taxon, occurring in the region of the Guianas and in Brazil (Schwartsburd et al. 2018). In Brazil, it is found in the Amazon and the Cerrado (Schwartsburd & Pena 2023; Fernandes et al. 2022). This is the first record for this species for the state of PiauÍ, where it has only been recorded growing in disturbed veredas and marshes in the PNNRP. Pteridium esculentum var. harpianum is characterized by simple distal segments, exceeding 4 cm in length, hairs on the secondary veins, and farinaceous appearance of laminae tissue between the veins.