PLANTS OF IOWA 82 



979. 0. tennis, Ag. 



This is the most common of the Oscillarias, being almost 

 universally present in stagnant water, and in slow 

 running streams, where water drops upon the soil, on 

 boards, etc., or stone under a water drop, very dense 

 mat. 



980. 0. limosa, Vauch. 



Next to the Tennis this is probably the commonest 

 species in the state. On damp earth, forming a thins 

 coating. Moist earth. 



981. 0. nigra, Vauch. 



Usualty floating free in stagnant water. In stagnant 

 ditch. 



982. 0. froelicliii, Kuetz. 



Floating among other algae in ponds. 



983. 0. frcelichii, var. fusca, Kirch. 

 On moist soil in the greenhouse. 



984. 0. princeps, Vauch. 



Pond, amid dense growth of Lemna. 



985. 0. imperator, Wood. 



The largest species of Oscillaria that is to be found irs 



the state. 

 MICROCOLEUS, (Desm.) Thur. 



986. M. vaginatus, (Vauch.) Comont. (M. terrestris, Eg.) 

 Damp ground. On flower pots in greenhouses. 



PHORMIDIUM. 



987. P. tenue, (Menegh.) Gomont. 



On pots in greenhouse. Pond. In pond among decay- 

 ing rushes. 

 LYNBYA, (Ag.) Thur. 



988. L. vulgaris, (Kuetz.) Kirch. 

 Damp soil. 



989. L. ockracea, (Kuetz.) Thur. 



In the trough of a flowing well. It is found very com- 

 monly in the water in this locality that are laden witb 

 iron, the sheath becoming impregnated with this sub- 

 stance. 



