Silvery-spleenwort, silvery glade fern, athyrie fausse-thélyptère

Asplenium acrostichoides Swartz, J. Bot. (Schrader) 1800(1): 54. 1800; Athyrium acrostichoides (Swartz) Diels; A. thelypterioides (Michaux) Desvaux; Diplazium acrostichoides (Swartz) Butters

Stems short-creeping. Petiole dark red-brown at base, straw-colored distally, 10--45 cm, swollen, with 2 rows of teeth; scales at base light brown, linear-lanceolate to lanceolate. Blade oblong-lanceolate, pinnate-pinnatifid, 30--80 × 12--25(--30) cm, narrowed to base, broadest near middle, acuminate at apex. Pinnae linear-oblong, base truncate, apex acuminate; segments oblong, margins entire to slightly lobed, apex round to slightly pointed. Costae and veins with multicellular hairs. Veins pinnate, lateral veins simple or 1-forked. Sori elongate, straight or hooked; indusia ± thick, margin ± entire. 2 n = 80.

Damp woods, often on slopes; 30--1500 m; N.B., N.S., Ont., P.E.I., Que.; Ala., Ark., Conn., Del., Ga., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.

Deparia acrostichoides belongs to sect. Lunathyrium . Closely related Asian ferns have been treated as conspecific with Deparia acrostichoides , but D . acrostichoides differs from them in having creeping stems with rather distant leaves and pinnate-pinnatifid leaves. Deparia acrostichoides and Asian species such as D . pycnosora (H. Christ) M. Kato and D . allantodioides (Beddome) M. Kato are examples of vicariant species pairs with amphipacific disjunct distributions.