FILICES. 89 



VI. VITTARIA Sm. GRASS FERN. 



Sori linear, continuous, in two-lipped marginal grooves or in 

 slightly intramarginal lines, with the unaltered edge of the frond 

 produced beyond and often rolled over them, but without spe- 

 cial indusia. Fronds narrow, grass-like. Veins free. Name 

 from Lat. vitta, a fillet or head-band. A tropical genus con- 

 taining 13 species. 



TvENiOPSis J. Sm. 



i. V. lineata Sm. Fronds 6' 18' long, i" 5" broad, nar- 

 rowed gradually downward to a stout compressed stem, the edge 

 often reflexed; sori in a broad intramarginal line in a slight 

 furrow, the edge of the frond at first wrapped over it. ( V. an- 

 gustifrons Michx.) Florida. 



VII. ADIANTUM L. MAIDENHAIR. 



Sori marginal, short, covered by a reflexed portion of :he 

 more or less altered margin of the frond, which .bears the spo- 

 rangia on its under side from the approximated tips of free, 

 forking veins. Name from Gr. a, without, and diaivao, to wet, 

 alluding to the smooth foliage. Includes over 80 species, 

 mostly from Tropical America. 



EU ADIANTUM. 



* Fronds at least bipinnate, pinnules flabellate or cuneate. 

 t Fronds smooth. 



1. A. capillus-veneris L. (VENUS' HAIR.) Stipes nearly 

 black, polished, very slender; fronds ovate-lanceolate, delicate, 

 bipinnate, the upper half or third simply pinnate ; pinnules and 

 upper pinnae wedge-obovate or rhomboid, rather long-stalked, 

 the upper margin rounded and more or less incised, crenate, 

 or acutely dentato-serrate, except where the margin is recurved 

 to form the lunulate separated indusia. Virginia, Kentucky, 

 and Florida to Utah and California. 



2. A. tenerum Swz. Stipes i high, erect, glossy; fronds 

 i 3 long, 9' 18' broad, deltoid, tri quadripinnate ; pinnules 

 articulated to their petioles, falling off at maturity, cuneate, the 

 upper edge rounded or somewhat angular, broadly, often rather 

 deeply lobed ; sori numerous, roundish, or transversely oblong. 

 Florida. 



