The Ferns of Washington 55 



MARSILIACEAE. Clover-fern Family. 



Perennial, rooted in mud; rhizome slender, creeping. 

 Leaves either filiform or 4-foliolate, long-petioled. 

 Spore-leaves modified into spore-bodies (sporocarps) 

 which are on peduncles arising near insertion of petiole 

 of foliage-leaf. Spores of 2 sizes. We have only the 

 following genus. 



MARSILIA. Clover Fern. . 



Aquatic or in wet places; rootstock slender, creeping. 



Leaves palmately 4-foliolate, resembling 4-leaved clover. 



Spore-leaves modified into spore-bodies (sporocarps) 



with two small teeth near base. (Honor of A. Marsili, 



an Italian botanist.) We have only the following 

 species. 



1. Marsilia vestita H. & G. (PI. 21, f. 1.) 



Petioles slender, 2-5 inches long; blade %-l inch in 

 diameter; leaflets wedge-shape or triangular to obovate, 

 entire or slightly toothed, covered with soft white hairs. 

 Spore-bodies (sporocarps) near leaf-base, on very short 

 petioles, \~% inch long, YtrM inch broad, densely 



covered with hair-like scales.— On wet silt or in shallow 

 water. British Columbia to Kansas and Arizona. 



SALVINIACEAE. Floating-fern Family. 



Plants floating, small, somewhat elongated, some- 

 times branched. Leaves apparently in 2 rows. Spore- 

 bodies (sporocarps) soft, thin-walled, 2 or more on the 

 same stalk. Spores of 2 sizes in separate sporocarps. 



We have orflv -Hip following crenus. 



AZOLLA. Duck-weed Fern. 



Plants moss-like, pinnately branched; rootlets be- 

 neath. Leaves dense, imbricated, minute, 2-lobed. 

 Smaller spore-bodies (sporocarps) acorn-shaped, con- 



