BRITISH DESMlDIEiE. 139 



******** Frond spinous or rough ivith spine-like granules which are 

 incrassated, emarginate, or divided*. 



t Spines minute, inconspicuous and granule-like . 



30. S. cyrtocerum (Breb.); frond rough with minute granules; seg- 

 ments in the front view somewhat triangular with short incurved 

 processes. 



Euastrinn , Bailey, American Journ. of Science arid Arts, v. 41. t. 1. 



f. 6 (1841). 

 Staurastrum cyrtocerum, Brebisson, in lit. cum icone (1846). 



Dolgelley and Penzance, J. R. Near Bristol, Mr. Broome. Piltdowii 

 Common and near Pulborough, Sussex, Mr. Jenner. 



United States, Baileij. Falaise, Brebisson. 



Froxid rather larger than that of Staurastrmn tricorne, deeply constricted 

 at the middle, rough with minute spine-like granules, which on the processes 

 are arranged in transverse lines. The segments are truncate and taper towards 

 their junction, so that the constriction forms a broad notch on each side. The 

 spines on the outer margin are larger than those on the rest of the segment, 

 and frequently are obscurely notched. The end view has three blunt angles, 

 much like those of Staurastrum tricorne, and usually a little curved. 



The sporangia are orbicular and their spines slightly forked at the apex. 



Staurastrum cyrtocerum is smaller than S. aculeatum and S. controversum, 

 and its spines are far less conspicuous. It is best distinguished by its con- 

 verging processes. 



Length of frond -g^ of an inch ; breadth -^-^ ; breadth at constriction 



1 



2 747' 



Tab. XXII. fig. 10. a. front view; b. end view. 



31. S. asperum (Breb.); segments elliptic or somewhat cuneiform, 

 rough with minute spines, which on the outer margin are usually 

 dilated at the end or forked. 



a. Angles in end view rounded. 



/3. proboscidemn, Br^b. ; angles in end view prolonged into short 



rays terminated by minute spines. 



Staurastrum asperum, Brebisson, in lit. cum icone (1846). 



Penzance, J. 11. Yate near Bristol, Mr. Broome and Mr. Thwaites. Near 

 Pulborough, Sussex, Mr. Jenner. 



Falaise, Brebisson. 



Frond comparatively large, rough vdth minute acute granules or spines ; 

 segments slightly tapering on the inner side, so that their figure is somewhat 

 cuneate, and the constriction forms a wide notch on each side. The outer 



* Staurastrum polymorphum has ocQa.s\onal\j a few scattered spines, but 

 they are simple. 



