110 Bulletin 313 



Melanconium fuligineum (S. & v.) Cav. — On the ripening fruit 

 of the grape. We have also found it very abundant on the very 

 small green berries, and pedicles in June. Causes a bitter rot of ripe 

 berries and dying of young berries and pedicles. Acervuli scattered 

 or grouped, grayish-cinereous, becoming brownish, subepidermal, 

 erunipent; conidiophores filiform, conidia ovoid to ellipsoid or very 

 much elongated, rounded or pointed, olive-colored, 9-12 x 4-6 /*. 



675. Cross- section of acervulus from fruit of grape, 2/3'. 676. Conidiophores 

 and conidia from different sources, 1/12. 677. Germinating conidia, 1/12. 



Marssonia BRUNNEAf (E. & E.) Sacc. — On the leaves of Populus 

 candicans. Causes numerous, small black spots which become con- 

 fluent, especially around the margins. Acervuli on both surfaces of 

 the leaf, 1-3 in each spot, pale, becoming black, erumpent; conidia 

 clavate, hyaline, 1 -septate; the two cells of unequal size, 14-16 x 

 5-7 /x. 



678. Spores, 1/12. 



Marssonia juglandis (Lib.) Sacc. (= Gnomonia leptostyla C. 

 & d. Not., page .58). — On the leaves of the walnut. Causes black 

 spots of irregular shape and size. AcervuU grouped on under sur- 

 face of the leaf; conidia ovoid, pointed at one end, truncate at the 

 other, slightly greenish in color, 1-septate, 8-10 x 4-5 fi. 



679. Infected leaflets of walnut. 680. Cross-section of acervulus, 2/3. 681. 

 Conidiophores and conidia, 1/12. 682. Conidia, 1/12. 



Marssonia martini Sacc. & Ell. — On the leaves of Quercus 

 alba. Causes small, ochre-colored spots on both surfaces of the leaf. 

 Acervuli in the tmder surface, globose, somewhat amber-colored; 

 conidia fusiform, slightly curved, acute at both ends, 1-septate, 

 slightly constricted, hyaline, 12-15 x 2.5-4 /x. 



683. Spores, 1/12. 



Marssonia ochroleuca* B. & C. — On the leaves of the chestnut. 

 Causes small pale brown or ashy-colored, circular, or oval, occasion- 

 ally confluent spots surrounded by narrow dark margins, 2-3 mm. in 

 diameter. Acervuli on under surface, few (1 to 5), pale, in center 

 of spots; spores hyaline, crescent-shaped ends slightly pointed, 1- 

 septate, 20-25 x 2.5-3 /*, oozing out in an amber-colored mass. 



684. Infected leaf of chestnut (Castanea dentata). "iSS. Spores from leaf 

 of C. dentata, 1/12. 686. Spores from leaf of C. vesca, 1/12. 



tThis genus has been recently changed to Marssonina. 

 *Syn. Septoria ochroleucn. 



