50 SALV1NIACEAE 



carries the sporangia on a series of short branches or lobes. (Named for Aloyxius 

 Mdrsili, an early Italian naturalist.) 



1. M. quadrifolia L. Leailets broadly obovate-cuneate, glabrous ; sporo- 

 carps usually 2 or 3 on a short peduncle from near the base of the petiole*, 

 pediceled, glabrous or somewhat hairy, the' basal teeth small, obtuse, or the 

 upper one acute. In water, the leaflets commonly floating on the surface ; 

 frequently cultivated and now somewhat extensively introduced from material 

 taken chiefly from Bantam Lake, Litchtield, Ct., where perhaps casually intro- 

 duced from Eu. 



2. M. vestita Hook. & Grev. Leaflets broadly cuneate, usually hairy, entire 

 (5-15 mm. long and broad) ; petioles 2-11 cm. long ; peduncles free from the 

 petiole, very short ; sporocarps solitary, hairy when young (about 4 mm. long), 

 with upper basal tooth longest, acute, straight or curved, lower tooth acute, the 

 sinus between them rounded. In swamps which become dry in summer ; la. 

 and southwestw. 



SALVINIACEAE 



Floating plants of small size, having a more or less elongated and sometimes 

 branching axis, bearing apparently distichous leaves ; sporocarps (son') very soft 

 and thin-walled, two or more on a common stalk, one-celled and having a 

 central, often branched receptacle which bears either macrosporangia containing 

 solitary macrospores, or microsporangia with numerous microspores. A small 

 and interesting family of plants without close affinity to other groups. 



1. AZ6LLA Lam. 



Small moss-like plants, the stems pinnately branched, covered with minute 

 2-lobed imbricated leaves, and emitting rootlets on the under side. Sporocarps 

 in pairs beneath the stem ; the smaller ones acorn-shaped, containing at the 

 base a single macrospore with a few attached bodies of doubtful function above 

 it ; the larger ones globose, and having a basal placenta which bears many 

 pedicellate microsporangia which contain masses of microspores. (Name not 

 satisfactorily explained.) 



1. A. caroliniana Willd. Plants somewhat deltoid in outline (6-25 mm. 

 broad), much branched ; leaves with ovate lobes, the lower lobe reddish, the 

 upper one green with a reddish border; macrospore with three attendant 

 corpuscles, its surface minutely granulate ; masses of microspores glochidiate. 

 Floating on quiet waters, from L. Ontario westw. and southw. Appearing like 

 a reddish hepatic moss. 



2. SALViNIA [Mich.] Adans. 



Leaves apparently 2-ranked, horizontally floating or subaerial, a third series 

 of foliar structures developed ventrally on the stem taking the form of fascicles of 

 root-like fibers. Sporangia subsessile, clustered, depressed-globose, longitu- 

 dinally sulcate, formed from the tips of short basal divisions of the filiform ven- 

 tral leaves. Sori basal within the fruit, the macrosporangia subsessile, the 

 microsporangia (in separate fruits) borne on filiform pedicels. (Named for 

 Prof. Antonio Maria Salvini of Florence, 1633-1729.) 



1. S. natans (L.) All. Foliage-leaves suborbicular-oblong, thickish, mostly 

 10-15 mm. long, hairy or papillose on both sides, the lower surface commonly 

 brownish or purplish. Marshes and ponds, Minn, and Mo. Long ago re- 

 ported by Pursh as "floating, like Lemna, on the surface of stagnant waters: 

 in several of the small lakes in the western parts of New York," but not 

 detected in this region by recent botanists. (Eurasia.) 



