THE FUNGI WHICH CAUSE PLANT DISEASE 305 



The promycelium is much branched but no sporidia are pro- 

 duced. 



The smut commonly affects the ovaries of Panicum and Setaria. 

 In America it has been collected on millet in several states. 



U. crus-galli T. & E.i^^ 



Sori often encircling stems at nodes or at the juncture of the 

 inflorescence, infecting both stem and leaves, prominent, often 

 nodular, one to several centimeters in length, protected by a tough 

 hispid membrane which upon rupture discloses an olive-brown 

 dusty spore-mass; spores ovoid to spherical, occasionally more 

 elongate, rather bluntly echinulate or even verruculose, chiefly 

 10-14 M in length. 



On Panicum crus-galli throughout the United States. 



U. bulgarica Bub. is on Sorghum vulgare. European. 



U. medians Bieden, oh barley, is closely like U. hordei."* 



U. scorzonerae (A. & S.) Schr. on Scorzonera is very close to 

 U. tragopogonis-pratensis. 



U. sacchari Rab.** 



Spore-mass black, spores globose or angularly globose, 8-18 ju 

 in diameter, oUve-brown or rufous, epispore thick, smooth. 



On sugar-cane throughout the tropics, especially in the old 

 world. 



In Java this fungus has been reported as the cause of serious 

 damage. Barrett observed it in Trinidad, where the damage was 

 less extensive. 



The leaves especially the young ones which have not yet sepa- 

 rated from each other are the parts affected. From the upper part 

 of the affected cane, as a rule, no secondary shoots arise, and those 

 which do arise from the lower part become infected in their turn. 

 The discolored whip-like structure at the end of an attacked cane 

 becomes dusty and black and contains the spores of the fungus. 



U. hordei (Pers.) K. & S.^"- »«• i^* 



Sori in spikelets, forming an adhering purple-black spore-mass, 

 about 6-10 mm. in length, covered rather permanently by the trans- 

 parent basal parts of the glumes; spores lighter colored on one side, 

 usually subspherical or spherical, smooth, 5-9 n, the most elongate 

 rarely 9-11 m in length. Common on barley. 



This was first recognized as distinct from the oat smut in 1591 



