74 OUR NATIVE FERNS AND THEIR ALLIES. 



often trilobed ; sporophyll long-stalked, much overtopping the 

 leaf, the panicle ample, 5' 8' long. California to British 

 Columbia. 



2. OSMUNDOPTERIS Milde. Bud pilose, enclosed in a 

 smooth upright cavity at one side of the lower part of the stalk. 

 ^ 15. B. Virginianum (L.) Swz. (RATTLESNAKE-FERN.) 

 Plant from a few inches to two feet high ; sterile segment ses- 

 sile above the middle of the stalk, broadly triangular, thinly 

 herbaceous, ternate; the short-stalked primary divisions once 

 to twice pinnate, then once or twice pinnatifid ; lobes oblong, 

 cut-toothed toward the apex ; fertile segment long-stalked, bi 

 tripinnate. Bud pilose, enclosed in a smooth upright cavity at 

 one side of the lower part of the stalk ; fertile segment recurved 

 its whole length, the longer sterile segment reclined upon it. 

 Reduced forms are B. gracile Pursh. {Botrypus Virginicus 

 Michx., Osmunda Virginiana L.) New Brunswick to Florida, 

 and westward to Arizona and the Pacific Coast. 



Family 2. HYMENOPHYLLACE^E Endl. 



Plant body consisting of a creeping stem bearing scattered 

 leaves of a filmy consistency, usually translucent. _ Sporangia 

 provided with a ring, sessile on a thread-like receptacle which 

 is surrounded at base by a cup-shaped or two-valved involucre. 

 The family contains several genera, mostly of tropical regions, 

 only one of which is represented in our flora. 



L TRICHOMANES Sm. FILMY-FERN. 

 Sori marginal, terminating a vein, more or less sunken in 

 the frond. Sporangia sessile on the lower part of a cylindrical, 

 filiform, often elongated receptacle. Indusia tubular or funnel- 

 shaped, entire or two-lipped at the mouth. Fronds delicate, 

 pellucid. Name from Gr. rpixofitaveS, the name of some fern, 

 from rpi'x, hair, and /taivojuai, producing frenzy, alluding to 

 some supposed property. A tropical and temperate genus con- 

 taining nearly 100 species. 



EUTRICHOMANES. 



i. T. Petersii Gray. Stipes i" 2" long; fronds 3" 10" 

 long, i" 2" broad, oblong-lanceolate or obovate, entire or vari- 



