Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
Pteridaceae
Species Description - Rhizomes erect; rhizome scales 8–12 x 0.5–1 mm, concolorous, golden brown, black with age, entire, prolonged into hair-like, uniseriate tips; fronds to 100 cm long, clumped; stipes 1/3–1/2 the frond length, dark reddish brown, glabrous except bases with dense golden brown scales varying to hair-like scales 2 mm long and sparse, minute clavate hairs less than 0.1 mm long; blades deltate to narrowly triangular, to 40 cm wide, broadest at bases, 1–2-pinnate-pinnatifid; pinnae inequilateral, exaggerated basiscopically, segments perpendicular to costae, ovate, glabrous adaxially, coriaceous, white-farinose abaxially, margins strongly recurved; veins free, depressed adaxially; sori elongate along veins, appearing as black specks scattered in the white farina; spores brown; 2n =240 (Jam).
Acrostichum ebeneum L., Sp. Pl. 2: 1071. 1753. Lectotype (chosen by Proctor, Brit. Fern Gaz. 9: 219. 1965). Jamaica. s. coll. s.n. (LINN-1245.14). Acrostichum tartareum Cav., Descr. Pl. 242. 1801. Pityrogramma tartarea (Cav.) Maxon, Contr. U.S. Natl. Herb. 17: 173. 1913. Type. Peru. Near Guamantanga, Ne´e s.n. (MA; isotype P, not found, photo US). Pityrogramma tripinnata Domin, Spisy Pr?ir. Fak. Karlovy Univ. 88: 7. 1928. Type. Mexico. San Luis Potosi´: Parry & Palmer 1004 (K!, photo GH, NY!, UC!; isotype NY!, US!). For additional synonymy, see R. Tryon (1962).
Although P. ebenea generally occurs at higher elevations than P. calomelanos, the two species occasionally grow together in Mexico. Pityrogramma ebenea is distinguished by the pinnules being broadest at the base and held nearly at right angles to the costae.