344 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
character separating it from the above species. Some botanists, 
however, consider all three as one species. Brefeld has described 
the germination to be the same as in Ustilago Avenae. Literature : 
27, 84. 
Ustilago Avenae (Pers.) Jens. 
Reticularia segetum Bull., Hist. Champ., pi. 4*2. 1791. p. p. 
Uredo segetum y Avenae Pers., Disp. Meth. Fung., 57. 1797. 
Uredo carbo DC., El. Fr., 6: 76. 1815. p.p. 
Ustilago segetum Ditm., Sturm’s Deutsch. El., iii, 1 : 67. 1817. p. p. 
Caeoma segetum Lk., Sp. PL, 6 2 : 1. 1825. p. p. 
Erysibe vera y Avenae Wallr., El. Crypt. Germ., 2 : 217. 1833. 
Uredo Carbo-Avenae Philipp., Traite Carie Charb., 91, pi. 2. 1837. 
Ustilago Carbo a vulgaris b Avenacea Tul., Ann. Sci. Nat., Bot., iii, 7: 80. 
1847. 
Ustilago segetum var. Avenae Jens., Om Ivorns. Brand., 61. 1888. 
Ustilago Avenae Jens., Le Charb. Cereales, 4. 1889. 
Ustilago Avenae f foliicola Aim., Rev. Agron., 1: 20-26. 1903. 
Exsiccati: Ustilago Avenae (Pers.) Jens., on Avena sativa, Seym. & 
Earle, Econ. Fungi, 81, Seym. &. Earle, Econ. Fungi, Clinton Ust. Supp. 
C 64, Shear, N. Y. Fungi, 82, Ell. & Ev., Fungi Col., 539 ; Ustilago 
segetum f. Avenae on Avena sativa, Ell., N. A. Fungi, 1092, p.p.; 
Uredo segetum , on Avena sativa, Rav. , Fungi Car., ii, 99. 
Sori in spikelets, forming a dusty olive brown spore mass, about 
6-12 mm. long by half as wide, usually rather completely destroying 
floral parts, eventually becoming dissipated; spores lighter colored 
on one side, subspherical to spherical though often more elongated, 
minutely echinulate, 5—9 p in length. 
Hosts: Avena fatua , Calif.; A. sativa , Ala., Calif., Conn., Ia., 
Ida., Ill., Ind., Ivans., Mass., Me., Mich., Miss., Mo., Mont., Neb., N. 
Car., N. Dak., N. IL, N. J., N. Mex., N. Y., Ohio, Okl, R. I., S. Dak., 
Tenn., Tex., Vt., Wash., Wise., W. Va., Wyo.; Nova Scotia. 
This smut is very common on cultivated oats and in the middle 
west often causes considerable injury. However, it can readily be 
prevented by seed treatment with hot water or formalin. Numerous 
experiment station workers have written bulletins relating to pre¬ 
vention experiments with this smut, among whom are the following : 
Arthur, Bolley, Clinton, Close, Ivellerman and Swingle, and Selby. 
It often occurs in the same field with Ustilago levis and sometimes 
the two are not easily distinguished. In rare instances it has been 
