42 THE FLORA OF NEBRASKA. 



Cosmarinm pulcherrimnm Nordst. Hedwigia 1870, 181. 



Small, oblong, ends rounded or slightly truncate, one seventh longer to double 

 the diameter, crenate, constriction deep, sinus narrow; half-cells semicir- 

 cular, inferior angles square, center inflated and furnished with about 5 

 rows of granules; membrane granulate, granules arranged in about 5 con- 

 centric series; diameter 33 fi, length 40 ji. 



Thedford. PI. VII., Fig, 14, a, b, c. 



Cosmarinm broomei Thwaites in Ralfs Brit. Desm. 103. 1818. 



About as long as broad, 30-50 y. in diam., constriction deep, linear, half-cells 

 quadrilateral, angles rounded, rough all over with minute granules; end 

 view twice as long as broad, slightly inflated in the middle; zygospore 

 orbicular, smooth. 

 Minden. PI. VII., Fig. 5, a, b. 



1 1. A \\\ \\ RODESM IS Ehrenb. Inf. 225. 1836. 



Choloroplasts axillary; cells simple, compressed, deeply constricted in the 

 middle; half-cells broader than long, with a single spine or mucro on each 

 side; zygospore smooth or aculeate. 



Etymology: Greek apdpov, joint, and cJeo/tof, chain. 



Arthrodesmns octocornis Ehrenb. Inf. 152. 1836. 



Cells smooth, 16-25 /i in diam., as long as wide, the sinus a wide, deep notch; 

 half-cells compressed, trapezoid, each angle truncated by one or two 

 straight, subulate, acute spines; zygospores globose, armed with long 

 spines. 



Minden. PI. VI., Figs. 12 and 12 a. 



12. EUASTRUJI Ehrenb. Infus. 162. 1836. 



Cells oblong or elliptical, deeply constricted into 2 half-cells which are emar- 

 ginate and usually incised at their ends, sides symmetrically sinuate 

 or lobed, provided with circularly inflated protuberances, end view ellip- 

 tical; zygospore globose, spinose, or tuberculate. 



Etymology: Greek ev, well, and aarpov, star. 



Enastrnm \ errucosu in Ehrenb. 1. c. 



Broadly ovate, 65-80 fi broad, 80-103 /n long, sinus broad, shallow; half-cells 3- 

 lobed; lobes triangular, divergent, truncate, or slightly concave at base, 

 with a large, central inflation on each side of which is a smaller one, and 

 2 inflations on the terminal lobes. 



Thedford. PL VII., Fig. 15 a, b. 



Enastrnm inerme (Ralfs) Lundell. Desm. Suec. 20. 1871. 

 Euastrum elegans inerme Ralfs. Brit. Desm. 89. 1848. 



Subelliptical, 32-38 /i in diam., sinus very narrow; half -cells subtriangular, 

 apex truncate, deeply incised, not dilated or dentate, sides bi-undulate, 

 the basal crenae most prominent; swellings 3, inconspicuous, sometimes 

 wanting. 

 Minden. PI. VII., Fig. 16. 



