EUASTRT7M. 97 



A. [NCUS, ! Ehrb.) Hass. Plate X X I V, figs. 1-10. 



Cells minute, smooth, as long as, or longer than broad, con- 

 striction a deep notch or sinns ; semicells with inner or lateral 

 margins turgid; miter, truncate ; spines diverging, subulate, 

 acute; sporangium orbicular, spinous ; spines subulate. 

 Diameter very variable 1036 ft. 



Turned up frequently in every State in which explorations 

 have been made. 



A. OCTOCORNI8, Ehrb. Plate XXIV, figs. 19-23. 



Smooth, about a- long as wide; the -inn- produced by a 

 deep constriction, a wide notch. Semicells much cum pressed, 

 trapezoid, each angle terminating by one or two subulate, 

 acute spines; the intervals between the spine- concave. Some 

 specimens without reference to size, have two -pine- at each 



angle. 



I )iameter 1625 u. 



Nut abundant, but scattered from Maine to Florida. 



Genus, EUASTRUM, Ehrb. 



Cells oblong >r elliptic, deeply constricted into two semicells 

 which are emarginate and usually incised at their end- ; sides sym- 

 metrically sinuate or lobed ; provided with circular inflated 

 protuberances (rarely absent); viewed from the vertex, elliptic. 

 Zygospores spherical, tuberculose <>v spinous. 



E. crassum, (Breb.) Kg. Plate XXV, figs. 1, 2, :;. 



('ell about twice a- long a- broad, smooth ; semicells three 

 lobed ; basal lube- very broad, with a wide shallow marginal 

 sinus ; terminal lobe cuneate, partly included in a notch formed 

 by the lateral lobes; incision in terminal lobe linear or acute 

 angled. 



Diameter 68-82 ;>.. 



A large, and not rare plant in shallow spring, and pond 

 waters. 



E. ORNATUM, Wood. Plate XXV. fig. 4. 



A species which is very close to K. crassum ; perhaps not 

 separable from it. The author, Wood, says "it differs in the 

 proportionate length, being only twice instead of three times 



