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.
Perennial fern 40 cm - 1.1 m tall Leaves: several, clustered, erect, herbaceous, deciduous, green, 30 - 80 cm long, 12 - 30 cm wide, oblong-lance-shaped in outline (widest near middle, narrowed to base, long tapering to pointed tip), but pinnately compound, with numerous multicellular hairs on "midrib" (rachis). Rhizome: short-creeping, horizontal, and covered with scales. Leaf stalks: clustered, erect, swollen at base, dark red-brown at bottom then straw-colored, 10 - 45 cm long, with two rows of teeth, and linear to lance-shaped, light brown scales at stalk base. Spores: 64 per sac, brownish, all of one kind, single-sectioned (monolete), oblong or kidney-shaped, and usually with a broad wing. The spores give rise to the gametophyte (the sexual phase of the plant), which is small, green, heart-shaped, hairless or often with glands or hairs, and sits above the ground.
Similar species: Deparia acrostichoides is probably most similar to Athyrium filix-femina var. angustum, but that fern has a more ascending rhizome, pinnae that are further divided into obviously toothed pinnules, much deeper grooves on the underside of the pinnae midveins (costae) that continue into the groove on the main leaf "midrib" (rachis), and the rachis, costae, and main veins are usually hairless though they may have a few pale glands. One may also confuse this species with some sterile leaves of Matteuccia struthiopteris var. pensylvanica, but that fern usually lacks hairs on its leaves, and it will never have spores and sori borne on the expanded green leaves, but rather on separate narrower, darkened, hardened leaves.
Habitat and ecology: Rare, in undisturbed mesic woods, or swampy ground.
Occurence in the Chicago region: native
Notes: There are about 50 species in the genus Deparia, but only two exist in North America. These two species have often been included in the genus Athyrium (this species then known as A. acrostichoides or A. thelypterioides), but research shows the two North American species to be most closely related to the other members of the genus Deparia. This is partially based on the presence of multicellular hairs on the leaf blades, and the discontinuous groove between the costae and rachis.
Etymology: Deparia comes from the Greek word depas, meaning saucer, referring to the saucer-like indusium of the type species. Acrostichoides means like the genus Acrostichum, which is from the Greek word acros, meaning tip, and stichos, meaning row, in reference to the distal spore-bearing pinnae.
Rhizome short-creeping, the lvs at the front end, 3.5-11 dm, the blade longer than the petiole, 13-22 cm wide, sharply acuminate, slightly reduced below, pinnate-pinnatifid, the rachis septate-hairy and sparsely scaly, pinnae 15-20 pairs below the pinnatifid tip, deeply pinnatifid, the costal wing 0.5-1 mm wide, the segments oblong, barely to strongly toothed, 6-13 נ3-6 mm; veins simple or forked, directed into the teeth; indusia 3-7 pairs per segment, light brown, firm, elongate, mostly 1.5-2 mm, straight or nearly so, seldom crossing the veins; 2n=80. Rich moist woods; N.S. and N.B. to Ont., and Minn., s. to Ga., La., and Okla. (Asplenium acrostichoides; Diplazium t.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.