SA L VINIA CE^E. 1 2 5 



ing peduncle, 3 4-celled ; macrospores 13 17 in each cell, 

 not constricted in the middle. Santa Barbara, California {Mrs. 

 Cooper), Arkansas (Xuttall), Oregon (Leiberg). 



Family 8. SALVINIACE^E. 



Floating plants with a more or less elongate and sometimes 

 branching axis bearing apparently distichous leaves. Sporo- 

 carps soft, thin-walled, two or more on a common stalk, i -celled, 

 with a central, often branched receptacle which bears macro- 

 sporangia containing a single macrospore, or microsporangia 

 containing numerous microspores. Consists of the two follow- 

 ing genera. 



I. Salvinia Schreb. Leaves 6'' 9" long, with a distinct 

 midrib. 



II. Azolla Lam. Leaves minute, numerous, closely imbri- 

 cate, deeply lobed. 



I. SALVINIA Schreb. 



Floating annuals with slender stems bearing small two- 

 ranked leaves. Sporocarps arranged in clusters, globose, mem- 

 branous, i 2 of each cluster containing 10 or more macro- 

 sporangia, the others containing numerous smaller microspo- 

 rangia. Named for Salvini, a Florentine professor. Contains 

 thirteen species, one of which is found with us. 



i. S. natans Hoffm. Leaves oblong, horizontal, rounded 

 or slightly cordate at base, i' i' long, bright green above, the 

 under surface matted with brown, pellucid hairs; sporocarps 

 48 in a cluster. (Marsztia natans L.) Bois Brule Bottoms, 

 Perry County, Missouri (Demetrzo.} Reported by Pursh from 

 Central New York ; the exact station unknown. 



II. AZOLLA Lam. 



Small, moss-like plants with pinnately branched stems cov- 

 ered with minute, imbricate, 2-lobed leaves, and emitting rootlets 

 beneath. Sporocarps of two kinds, borne in the axils of the 

 leaves. Smaller sporocarps ovoid, containing a single macro- 

 spore at the base. Larger sporocarps globose, producing from 

 the base many pedicelled sporangia, containing several masses 



