07- iiYnuorTEijinKS. 



tbrkini,', and tc'rM)inatt.(l li.v tlic sliort (4"-G") noiltliiiK si)ike ; leaves aliout 

 G-rowed, liiieiir-siibulate, entire, spreading or recurved ; lliose of llie sjjike 

 ovate, acuminate, witli l)ristly margins. — Springy sandy places. East I'^lorida 

 {Curtiss}, and Alabama (Mu/tr). 



Order HYDROPTERIDES. 



MARSILIA, L. 



Plants with filiform creeping stems, a whorl of 4 wetlge-shaped leaves at 

 tiie summit of a long erect petiole, and one or more globular sporangia 

 borne on a slender stalk at the base of the petioles, each divided into sev- 

 eral partitions, which contain the larger and smaller spores. 



S. uncinata, A. Braun. Stem long ; leaves smooth or hairy ; sporangia 

 oval, compressed, half as h)ng as the peduncle. — Banks of the Mississippi 

 below Vicksburg. 



ISOETES, L. 



I. melanospora, Engelm. Small, mostly monoecious; leaves few (.5- 

 10), distichous (^'-2^' long) ; spore cases covered by the thin edges of the 

 cavity (velum); larger spores blackish, very minutely warty, the smaller 

 ones dull, papillose. (Eiigelmann.) — In shallow depressions on the summit 

 Stone Mountain, Georgia (Engelmann, Sfc). 



I. Engelmanni, A. Braun, var. Georgiana, Engelm. Leaves 10'- 12' 

 long, rather slender, stomatose ; spore-cases oval, with narrow velum ; larger 

 spores and smaller spores smooth. — Slow-flowing water in Ilorseleg Creek, 

 mountains of Georgia. 



I. Butleri, Engelm. Dioecious; trunk nearly globose; leaves 8-12, 

 bright green, 3' -7' long; spore-cases usually oblong, spotted, the velum very 

 narrow, or none ; ligule subulate, from a triangular base ; larger spores 

 warty, smaller spores dark brown, papillose. [Einjelmann.) — Barrens of Ten- 

 nessee i^Dr. Gattinyer), and westward. 



