378 THALLOPHYTES 



Other Ascomycetes. A study of a few types of the Ascomy- 

 cetes has given a general notion of their habits but no notion 

 at all of their extensive number. However, with this general 

 acquaintance, other forms can be easily understood. Some other 

 common destructive forms are the Apple and Pear Scab l (Fig. 

 330), the Bitter Rot of Apples 2 (Fig. 331), Peach Mildew, 3 Black 



FIG. 330. Apple attacked by Scab, Venturia Pomi. Photographed 



by Whetzel. 



Rot of Grapes, 4 and the Wilt disease of Cotton, Watermelons, 

 and Cowpeas, 5 etc. 



Summary of Ascomycetes. The Ascomycetes have no water 

 habits and their chief resemblance to the Algae is in the character 

 of their sex organs and fruiting bodies. The plant body ranges 



1 A Contribution to Our Knowledge of Apple Scab. Bulletin 96, Mon- 

 tana Agr. Col. Exp. Sta., 1914. 



2 Bitter Rot of Apples. Bulletin 44, Bur. PL Ind., U. S. Dept. of Agricul- 

 ture, 1903. 



3 Peach Mildew. Bulletin 107, Colorado Agr. Exp. Sta., 1906. 



4 The Control of Black-Rot of Grape. Bulletin 155, Bur. PI. Ind., U. S. 

 Dept. Agriculture, 1909. 



5 Wilt Disease of Cotton, Watermelon, and Cowpea. Bulletin 17, Division 

 of Vegetable Path., U. S. Dept. Agriculture, 1899. 



Also see Spraying Practice for Orchard and Garden. Bulletin 127, Iowa 

 Agr. Exp. Sta., 1912. 



