Swamp ferns of medium size, with dimorphous leaves, the sterile ones spreading, with deeply pinnatifid blades, the veins copiously anastomosing; fertile leaves rigidly erect, the pinnae somewhat foliaceous, but greatly reduced in width, with a single series of elongate costal areoles and a few short excurrent veinlets. Sori in a single row, linear to elliptic, borne as in Anchistea, superficial, sometimes appearing immersed from the pustulate membranous leaf-tissue beneath. Indusium extrorse, firmly membranous, persistent and scarcely reflexed with age. [Name in honor of Gustav Lorinser, an Austrian physician and botanist.]

A monotypic genus of eastern North America.

1. Lorinseria Areolata (L.) Presl. Net-Veined Chain-Fern

Fig. 55

Acrostichum areolatum L. Sp. PI. 1069. 1753. Woodwardia angustifolia J. E. Smith, Mem.

Acad. Turin 5: 411. 1793. Lorinseria areolata Presl. Epim. Bot. 72. 1851. Woodvardia areolata Moore, Ind. Fil. xlv. 1857,

Rootstock slender, widely creeping, chaffy, with scattered leaves. Fertile leaves erect, surpassing the sterile; stipes 1°-2° long, stout, puplish-brown, lustrous; blades 6'-12' long, ovate-oblong; pinnae linear, distant, usually connected by a slight wing. Sterile leaves spreading; stipes 6'-14' long, slender, greenish; blades 6'-15' long, ovate-oblong to deltoid-ovate, acuminate, membranous, deeply pinna-tifid; pinnae linear-lanceolate to oblong-lanceolate, acute, lightly or sometimes deeply sinuate, serrulate, usually connected by a variable wing, or the lower pairs free; veins joined in numerous hexagonal areoles.

In swamps and moist soil, Maine to Florida, Tennessee, Louisiana, and Arkansas; also in Michigan. Aug.-Oct. Called also Netted chain-fern. Various imperfectly fertile forms occur.