THE AZOLLAS. 



=^0^ HE azollas are the members of the Salvin- 



' ^--1 iacese oftenest called the water ferns, 



^^^ and their finely divided fern-like fronds 



il^''' well merit the name. Though few in 



.^f.%, t. number of species, and small and deli- 



-''■^' cate as individuals, they have a wide 



distribution and are found in all the warmer parts of the 



world. In North America we have two species, one 



Western and the other with a wider ransfe. 



Azolla Caroliniana. 



If asked to name the smallest of the North American 

 fern allies one need have no hesitancy in mentioning 

 Asolla Caroliniana. With the exception of its Western 

 congener there are no others that even approach its 

 diminutive proportions. Three or four full-grown plants 

 may be hidden under a single copper cent, and yet so 

 abundant is this species that vast stretches of water are 

 often completely covered by it. 



Taken singly, the plant is a handsome one. Its stems, 

 so slender as to be invisible to the eye, fork several 

 times, and are covered with the tiniest of two-lobed over- 

 lapping leaves, from pale green to deep red in colour. 



