GRASSES OF IOWA. 225 



beyond. Seymour* observes that the thicker the cell-walls 

 which the mycelium penetrates, the more abundant are the 

 haustoria. In later stages of the fungus the mycelium extends 

 through and into the cells of its host, becoming densely packed, 

 but not much beyond the point of infectioa. The mycelium 

 has a peculiar glistening opalescent appearance. In course 

 of time spores are formed from the branching mycelium by 

 abstriction; in this way a chain of spores is formed. In appear- 

 ance and color these parts do not differ essentially from the 

 mycelium. The protoplasm is highly granular, the cell-walls 

 become gelatinous; these walls later are absorbed, so that little 

 else than a mass of black spores remain. As a result of the 

 infection, the host develops an increasing number of thin- 

 walled parenchyma cells. This is due to the action of the 

 fuDgus. 



Hosts. — Corn smut occurs on but two host plants so far as 

 known. Corn is, of course, the common host plant, but Trelease 

 has also collected the fungus on Teosinte [Euchlaena Mexicana), 

 and it may be expected on related genera. 



Distribution and damage. — The fungus is found wherever 

 corn is grown. Botanical writers refer t ) it in Iowa, Wiscon- 

 sin, the Carolinas, New Jersey, Indiana, Kansas and Texas, f I 

 have examined specimens from Illinois, New York and Massa- 

 chusetts. European mycologists report it from Italy, Ger- 



*Smut of Indian corn (L"»(iJaaoZea Mays). Rept. U. S. Dept, of Agrl. 1887: 380-383. 



tTuckerman and Frost. Cat. PI. Amherst CoU. 83. 



Day. Cat. of Nat. and Native Plants of Buffalo. 143. 



Ellis in Briton. PI. of New Jersey. 506. 



Trelease. Parasitic Fung of Wis. 3i. 



Schwienltz. Syn. Fungi. Car. 71. 



Bessey. Bull. Bot. Dept. Iowa Agrl. College. 1884:12". 



Ravenel. Fung. Car. Ex. IV. 100. 



Kellerman. Bull. Kan. Agrl. Coll. Exp. Sta. 23. 



Bull. Neb. Agrl. Coll. Exp. Sta. 11: 67. 



Norton. Trans. Acad. Sol. St. Louis. 7: 234. 



H. S. Jennings. Bull. Texas Agrl. Coll. Exp. Sta. 9: 29, 



Hitchcock and Norton. Bull. Kan. Agrl. Exp. Sta. 62. 



Kellerman & Werner. Cat. of Ohio Plants. 347. 



Seymour. Rep, U. S. Dept. of Agrl. 1887: 380. 



Peck. Rep. State Mus. Nat. Hist. 34: 26. 



Webber. Cat. of Flora of Neb. 73. 



Bessey. Bull. Neb. Exp. Sta. 11: 21. 



F. Lamson-Scribner. U. S. Dept. of Agrl. Rep. 1887:385. 



14 



