606 HYDROPTEKITVEK. (mARSILEACE^e) . 



New Hampshire, often partly emersed : probably throughout the Middle 

 States. 



3. I. Eaigcliurimai, Braun. Leaves long and slender (9'- 12' long), 

 entirely emersed in summer, soil and flaeeid, light yellowish-green, the dilated 

 base longer than broad ; spores coarsely farinaceous and reticulated. — Shallow 

 ponds of the Western States, and southward. 



2. AZOLLA, Lam. Azolla. (Tab. 14.) 



Plant floating free, pinnately branched, clothed with minute imbricated leaves, 

 appearing like a small Jungermaunia : fructification sessile on the under side of 

 the branches, of 2 sorts. Sporocarps covered at first with an indusium of a 

 single diaphanous membrane, ovoid ; the smaller kind opening transversely all 

 round, containing several roundish-angular antheridia ? pcltately borne on the 

 sides of a central erect column : the large or fertile kind bursting irregularly, 

 filled with numerous spherical sporangia rising from the base on slender stalks, 

 each containing a few globular spores. (Name said to come from a£o>, to dry, 

 and 6'XXo), to kill, being destroyed by dryness.) 



1. A. Ca»'Oliaaiii88ia, Willd. Leaves ovate-oblong, obtuse, spreading, 

 reddish underneath, beset with a few bristles. — Pools and lakes, New York to 

 Illinois, and southward. — Plant \' to 1' broad. — Probably the same as A. 

 Magellan ica of all South America. 



Marsilea mucronata and perhaps M. vestIta may occur in the western 

 parts of Illinois and Wisconsin. See Addend. 



SALvfsiA natans, L., said by Pursh to grow floating on the surface of 

 small lakes in W. New York, has not been found by any other person, and prob- 

 ably does not occur in this country. It is therefore omitted. 



