The Diatoms of Nebraska 139 



apices rounded or sub-rostrate; carinal dots slightly elongated, 

 9-10 in 10 /a; striations fine, 20—24 in 10^. 



In ditch by railroad : Culbertson. 



16. Homoeocladia commutata (Grun.) Kuntze. Rev. Gen. Plant.. 



Ill, p. 408. 1898. 

 Nitsschia commutata Grun. in CI. & Grun. Arct. Diat., p. /p. 



1880. 

 PI. 19, figs. 726-728; pi. 23, fig. 858. 



Linear, 34-73 /x, long, 8— I7)ii wide, constricted in the middle, 

 apices attenuate-rostrate; keel marginal with round dots, 8-10 in 

 10 fx,, the two middle ones more distant; striations 21-24 ^^ 10 fx. 



In ponds and creeks : Anselmo, Grand Island. Lincoln, Trenton. 

 Devils Lake and fresh water near Devils Lake, N. Dak. 



17. Homoeocladia umbonata (Ehr.) Kuntze. Rev. Gen. Plant., 



Ill, p. 40p. i8p8. 

 Navicula umbonata Ehr. Abh., p. ^6. 18^6. 

 Nitzschia thermalis (Ehr.) Auersw. in Rabcnh. Alg., Nos. 1064 



and 1266. 

 PI. 19, fig. 729. 



Linear-lanceolate or oblong, 80-100 /x long, 9-10 /x wide, slightly 

 constricted in the middle, making the cell somewhat curved, apices 

 cuneate ; keel marginal with round dots, 7-8 in 10 /x,; striations 

 about 28 in 10 fx. 



Talmage. 



9. Apiculatae 



/]. Keel with very distinct dots. 18. H. hnngarica. 



AA. Keel with indistinct dots. 19. H. apiculata. 



18. Homoeocladia hungarica (Grun.) Kuntze. Rev. Gen. Plant., 



III. p. 4op. i8p8. 

 NitzscJiia hungarica Grun. in Wien. Verh., p. ^68, pi. 22, fig. 15. 



1862. 

 PI. 19, figs. 730-735. 



Linear, usually constricted in the middle, 48-1 10 /x. long, 8-1 i/x. 

 wide, apices slightly acuminate, acute or truncate; keel marginal 

 with 7-1 1 dots in lO/x,; striations 15-20 in lO/x, interrupted 

 through the middle by a longitudinal sulcus. 



