140 Clarence J. Elmore 



In creeks, springs, tanks, ponds, etc. ; in brackish water at Arbor : Arbor, 

 Ashland, Auburn, Blue Springs, Cedar Creek, Culbertson, Fairbury, Grand 

 Island, Hyannis, Lincoln, Louisville, Oakdale. Omaha, Orleans, Ruby, 

 Salem, Scottsbluff, Seneca, Seward, Stromsburg, Talmage, Trenton, Wann. 



Belvidere, Little White River, Norris, Rapid City, Rosebud, S. Dak. ; 

 Devils Lake and fresh water near Devils Lake, N. Dak.; Stockton, Cal. 



19. Homoeocladia apiculata (Greg.) Kuiitze. Rev. Gen. Plant., 



Ill, p. 408. 1898. 

 Nitcsc/iia apiculata (Greg.) Grun. in CI. & Grim. Arct. Diat., 



p. 73. 1880. 

 Tryblionclla apiculata Greg, in Mic. Jour., V, p. 79, pi. i, fig. 3. 

 PI. 19, fig. 736. 



Linear, more or less constricted in the middle and below the 

 apices, 25-34 /a long, 6-8 /x vi^ide, apices apiculate, sometimes trun- 

 cate ; keel marginal with no visible dots ; striations broken by the 

 narrow sulcus, 15-19 in 10 /a. 



In jar in laboratory, Lincoln; roadside ditch. Grand Island; North Platte, 

 Scottsbluff. 



10. Lanceolatae 



A. Connecting zone very broad and plicate. 20. H. lanceolata. 



AA. Connecting zone narrow. 



b. Middle carinal dots more distant than the others. 



c. Striations 30-32 in 10 m. 21. H. subfilis. 



cc. Striations about 24 in 10 m. 22. H. intermedia, 



bb. Carinal dots all equidistant. 



c. Striations distinct, 16-17 in 10 a*. 23. H. amphibia, 



cc. Striations indistinct, more than 20 in 10 M. 



d. Lanceolate, striations very delicate, 30-36 in 10 i«. 



24. H. palca. 

 dd. Narrowly lanceolate, striations more easily seen, 20-22 in 

 10 M. 25. H. frustuluni. 



20. Homoeocladia lanceolata (W. Sm.) Kuntze. Rev. Gen. 



Plant., III. p. 409. 1898. 

 Nitzschia lanceolata W. Sm. Brit. Diat., I, p. 40, pi. 14, fig. 



118. i8fi3. 

 PI. 19, figs. 737-739- 



Narrowly lanceolate, 66-200 /x long, 8-17.5^ wide, apices acute, 

 sometimes attenuate and rostrate ; keel marginal with rounded dots. 



