This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Rootstock short-creeping, the fertile leaves upright, usually much surpassing the spreading sterile ones. Stipes densely tufted, purplish or reddish brown, shining, 1-5 long; blades linear-oblanceolate, 8'-15' long, 1'-2 1/2' wide above the middle, firm, once pinnate, the rachis like the stipes; pinnae 20-40 pairs, lanceolate, subfalcate, alternate or partly so, sessile, crenate, serrate or incised, auricled on the upper side at the base and occasionally also on the lower; lower pinnae gradually smaller and oblong or triangular; sori numerous, oblique, linear-oblong, nearer the midvein than the margin, often confluent with age.
On rocks and banks, preferring limestone soil, Maine and Ontario to Colorado, southward to Texas and the Gulf states generally. Ascends to 4200 ft. in North Carolina. Erroneously ascribed to Jamaica. South African specimens, however, are identical. Several deeply incised or pinnatifid forms have been described from the United States. July-Sept.
Asplenium Trichomanes L. Sp. PI. 1080. 1753.
Rootstock short, nearly erect, chaffy with blackish scales. Stipes densely tufted, commonly numerous, l'-2 1/2' long, purplish-brown and shining; blades linear, often somewhat reduced toward the base, 3'-8' long, 4"-9" wide, rather rigid, once pinnate, evergreen, the rachis dark brownish; pinnae mostly oval or roundish-oblong, inequilateral, partly opposite, partly alternate, or nearly all opposite, cuneate at the base, the margins slightly crenate; lower pinnae smaller and relatively broader, farther apart, often fan-shaped in outline; sori 3-6 pairs, short, commonly confluent at maturity; spo-ranges dark brown.
On rocks, preferring limestone, throughout nearly the whole of North America north of Mexico except the extreme north. Ascends to 2500 ft. in Vermont. Also in Europe and Asia. July-Sept. Called also Wall- or dwarf-spleenwort; water-wort, english maiden-hair.
Asplenium viride Huds. Fl. Angl. 385. 1762.
Rootstock stout, creeping, chaffy with brown nerveless scales, the leaves usually borne in dense tufts. Stipes numerous, stout or sometimes very slender, brownish below, green above, 1'-3' long; blades linear-lanceolate, 2'-8' long, 4"-10" wide, once pinnate, pale green, soft-herbaceous or almost membranous; rachis green; pinnae 12-20 pairs, roundish-ovate or rhombic, deeply crenate, obtuse, unequal-sided, broadly cuneate at the base, the lower side obliquely truncate; sori near the midvein, oblong, usually numerous and confluent, or sometimes fewer and somewhat apart.
On rocks, Quebec and New Brunswick to Alaska, south to Washington, Wyoming, and the Green Mountains of Vermont. Also in Europe and Asia. Summer.