Asplenium scalifolium E. P. St. John; A. suare E. P. St. John; A. subtile E. P. St. John.

Roots proliferous. Stems erect, unbranched; scales blackish throughout, linear to narrowly triangular, 0.9--1.3 × 0.1--0.4 mm, margins entire. Leaves monomorphic. Petiole brownish black, 0.5--3(--5) cm, 1/9--1/7 length of blade; indument of blackish, linear-lanceolate scales at base. Blade narrowly lanceolate, 2--3-pinnate, (4--)10--20(--)30 × 1--3(--5) cm, thin, glabrous; base tapered somewhat; apex formed by gradual reduction, not rooting. Rachis blackish brown, dull, essentially glabrous. Pinnae in (8--)12--16(--22) pairs, oblong; medial pinnae 0.5--2.5 × 3--10 mm; base cuneate; apex obtuse. Pinnules of 1--5 segments; segments oblanceolate, 2--3 × 1--2 mm, entire; apex mostly round. Veins free, evident, 1 per segment. Sori 1 per segment. Spores 64 per sporangium. 2n = 144.

Limestone outcrops in grottoes, on cliffs, and on boulders in shaded woods; 0--50 m; Fla.

This delicate spleenwort, Asplenium verecundum , occurs in both southern and central peninsular Florida where it is very local. Sterile hybrids are known to result from crossing with A . trichomanes-dentatum ( A . × biscayneanum) and A . abscissum ( A . × curtissii ).

Asplenium verecundum may be a variety or cytotype of the similar A . myriophyllum (Swartz) C. Presl of the West Indies (D. B. Lellinger 1985).