78 



This plant has much in common with some varieties of St. 

 gracile, Ralfs, but is more robust, has quadrangular semi- 

 cells, is larger, and is furnished with teeth near the sinus. 



Staurastrum botrophilum, n. sp. St mediocre, 

 paulo longius quam latius, distincte granulosum; granulis in 

 series reguläres ordinatis; a fronte, semicellulis triangulari- 

 bus, angulis inferioribus rotundatis subito in dorsum late 

 truncatis, a lateribus, late ellipticis divergentibus, a vertice, 

 triangularibus. Diam. .0015" — .0016". Hab. Swampy places 

 near Bethlehem, Pa. This form belongs to a class like St. 

 pygmaeum, Breb., St. punctulatum, Breb., St rugu- 

 losum, Breb., etc., but is separated by the Cosmarium-like, 

 truncate form as seen in front view. 



Staurastrum Pringlei, n. sp. St parvum, distincte 

 gr. rulatum, tarn longum quam latum, medio plus minus 

 constrictum; sinu acutangulo ampliato; semicellulis sub- 

 triangularibus, lateribus rotundatis, dorso subplanis, medio 

 convexis, subapice retusis, angulis acutis; a vertice visis tri- 

 vel tetragonis; in forma trigona lateribus fere rectis; in forma 

 tetragona retusis, angulis acutis. Diam. .0011" — 0013". 

 Hab. Nebraska Notch, Vt Collected by C. G. Pringle. 

 The form nearest to this is St. Kjellmani, Wille, collected 

 in Nova Zembla, but it differs in size and in proportions of 

 length to breadth ; in having the angles acute, not rounded, 

 and turned upward in the direction of the sides, not straight; 

 in having triangulär, not elliptical semicells; and in its 

 back being straight, elevated in the centre, and retuse, not 

 rounded. 



Staurastrum Donnellii, n. sp. St parvum, duplo 

 longius quam latius , oblongo - quadratum ; cytiodermate 

 punctato et sulcato; semicellulis quadratis, angulis basalibus 

 rotundatis, lateribus leviter sinuato-retusis ; angulis superiori- 

 bus (quatuor) in cornu breve obtusum divergenter produc- 

 tis; a vertice visis, quadrangularibus. Diam. .0006". Hab, 

 Florida. Collected by Capt John Donneil Smith. The 

 form nearest this plant is St. pileolatum, Br^b., but it 

 differs in having the ends furnished with three conicai pro- 

 cesses, and in being triangulär in end-view. 



Staurastrum pentacladum, n. sp. St. mediocre, 

 granulato-asperum ; semicellulis ventre inflatis, dorso rotun- 

 datis, angulis in cornu apice distincte trifurcatum productis; 

 a vertice visis quinque-radiatis: radiis substrictis, margine 

 serrato-dentata. Diam. .0015". Hab. Splitrock Pond, New 

 Jersey, July, 1880. St. gracile, Ralfs, comes near this 

 form, but its end-view is triradiate. N. Wille, of Norway, 

 has published a variety, nanum, which is quadriradiate. 



