THE FLORA <>F NEBRASK \. L' I 



Oscillaria yiolacea Wallbotb Flor. Crypt. Germ. L8. 



Filaments long, straight, radiating, forming a gray-violet, membranaceous 

 stratum, the ends somewhat reduced and ofteu drawn out to a thin 

 point, 4 5 " in diam.; articulations half the diameter in length. 

 In greenhouse at the University. PI. I., Pig. L3. 

 Oscillaria tenuis Ao. Syst. Alg. 60. 1824. 



Oscillaria viridis Kuetz. Phyc. Geuer. 1st;. L843. 



Stratum bright green, brownish with age; filaments ligh( aeruginous, 

 straight, usually slightly constricted at the joints, 1 1" broad, 

 si raight or curved, not attenuate or capitate; articulations balf as long 

 as broad, or before division twice as long; cell-contents finely granular. 

 Hocks, pools, margins of ponds, or float ing free; common I hroughoul t he Btate 

 PI. I., Fig. 1G. 

 Oscillaria limosn Ac. 1. c. 6G. 



Filaments rigid, straight, actively oscillating, blue green, interwoven In a 

 thin, mucilaginous, radiating, green stratum, distinctly articulate; i ints 

 nearly equal to, or a little longer than broad, after division half a^ long 

 as broad; apex straight or curved, somewhat attenuated: cell contents 

 homogeneous or occasionally slightly granular; filaments 6 

 diam. 

 Common on damp earth, forming a blue-green coating. 

 Oscillaria froelichii Kuetz. Phyc. Gener. 189. 1843. 



Stratum dark steel-blue or olive-green, in age purple; filaments nearly 

 straight, even, not attenuated; articulations one-half to even one-sixth 

 the diameter; contents aeruginous to olive-green, coarsely granular. 

 Gomont unites this species with the preceding. 

 Var. viridis Zellkr.— Stratum green; filaments about 15 // in diam.. en Is Blightly 



curved. Among other algae, as VaucJu ria, Spirogyra, etc. 

 Var. fusca Kirch.— Very dark olive -brown or purple; cell contents olive-green; fila- 

 ments 12-18 fi in diam. 

 Very common on pots and damp soil in greenhouses, Lincoln. PL I.. Fig.14. 

 Oscillaria princeps Vauch. Hist. Conf. 190. 1803. 



Oscillaria imperator Wood Proc. Am. Phil. Sue. XL, 1-1. 1869. 



Stratum dark green; filaments steel-blue, straight and rigid, somewhat thin 

 ner towards the ends; apex broadly rounded; articulations one fourth to 

 one-fifth as long as broad; diameterof filaments 25 15//. 

 Occasionally found among other algae in the Dismal River region, and in 

 many places in the eastern part of the state, l'l. 1 . Fig. IT. 



L.YNGBYA Ao. Syst. Alg., 7.'5. 1824. 



Filaments sheathed, simple, tree or aggregated into an intricate stratum, 

 never constricted at the joints; apex straight, blunt, or slightly attenuab 

 sheath broad or narrow, lamellose, hyaline or rarely yellowish brown. 

 Etymology: dedicated to Lyngbye, a Danish phycologist 

 Lyngbya aestuarii (-Hoffman-Bang) Liebman Kroyer's Tidskr. L84L, p. 192. 

 Oscillatoria aestuarii Hoffman Bang De Usu Conferv. 16. 1814 (Ex Qomonl . 

 Filaments rigid, flexuose, blue-green, granular, densely interwoven in dark 

 blue-green tufts; joints one-third to one-sixth as long as wide; sheaths 

 hyaline, becoming brownish and lamellose with age; diameterof thread 

 20 26 fi, withoul sheath, 11 18/*. 

 In mineral water; Lincoln. Franklin. PI 1 1 , Fig. 25. 



