Curtiss's spleenwort

Roots proliferous. Stems erect, unbranched; scales blackish throughout, narrowly deltate, 1 × 0.2 mm, margins entire. Leaves monomorphic. Petiole brownish black, 3--10(--15) cm, 1/3--2/5 length of blade; indument of blackish, narrowly lanceolate scales at base. Blade oblong-lanceolate, 2-pinnate, 10--30 × (1.5--)5--10 cm, thin, glabrous; base not or only slightly tapered; apex gradually narrowing, not rooting. Rachis blackish to green, dull, nearly glabrous. Pinnae in (7--)14--22 pairs, oblong; medial pinnae 1--6 × 0.5--1.5 cm; base truncate; apex pointed. Pinnules linear to fan-shaped to unequally pinnate, 3--9 × 1--7 mm, mostly notched apically. Veins free, evident. Sori 1--4 per segment, usually more on acroscopic side. Spores abortive. 2 n = 108.

Shaded damp limestone rocks; 0--50 m; Fla.

Asplenium × curtissii , sterile and with irregular meiosis, is the product of hybridization between A . abscissum and A . verecundum and occurs with them in central Florida, sometimes forming large colonies by root proliferation. It can readily be separated from A . abscissum by its pinnate blades. From A . verecundum it can be distinguished by its relatively long petioles and less divided blades. Asplenium × curtissi is known only from several localities in north central Florida. It makes a showy conservatory plant.