151 ]\Iycologia 



sunken, usually deeper in color than the healthy part, changing the 

 underlying tissue to brown or dark-brown, tissue becoming spongy, 

 imparting slightly bitter taste; hyphae intercellular, septate, 2-5 /x 

 diam., readily producing chlamydospores and cylindrospores in 

 culture; chlamydospores (formed in culture) catenulate, cinereous 

 or greenish, thick-walled, conspicuously constricted at the junc- 

 tion, numerously granulate, 10-14 X 5-8 /a; cylindrospores (formed 

 in culture from fruit spot) straight or curved, tapering toward 

 the apex, pale pinkish-brown in mass, colorless or indistinctly 

 greenish when observed alone, 2-7-septate, occasionally con- 

 stricted at septum, 38-70 X 3-3-5 ;«, those obtained from leaves in 

 culture measuring 32-80 X 3-4 /«■ ; pycnidia, formed as brownish 

 black spots on the surface of entirely decayed fruit, numer- 

 ous, irregular or often growing in concentric zones, after- 

 wards covered by white or pale olivaceous-white cottony hyphae, 

 semi-spherical, 70-220 X 70-130 /x, at full maturity exuding 

 from the central opening, a pinkish-brown semi-liquid sub- 

 stance composed of two kinds of pycnospores, characteris- 

 tic of the genus Phomopsis; conidiospores 15-18 X 2-3 /x; 

 Phoma-spore ellipsoidal, pointed rather distinctly at both ends, 

 contiunous, hyaline, guttulate at both ends, 7-9 X 3-4 1^- ', Septoria- 

 spore filiform, slightly curved either near the apex or at the 

 middle, continuous, hyaline, 24-32 X 1-3 Ai ; stromata formed in 

 culture and on decayed twigs placed on culture media, irregular, 

 black outside, white inside, 3-7 mm. diam., producing flat, cen- 

 tral Phomosis pycnidia of about 1-1.5 nim. diam., and a certain 

 number of surrounding Diaporthe perithecia with protruding 

 ostiola visible to the naked eye; perithecia (observed on twigs 

 above mentioned) spheroidal or oblate-spheroidal, 300-450 /a 

 diam., with intensely black outer wall and light-brown inner wall ; 

 ostiola rather long, conspicuously hairy near the end, with pro- 

 jecting hyphae; asci fusoid, obtuse above, inconspicuously pedicel- 

 late below, 45-52 X 5-io/x, octosporous, aparaphysate; ascospores 

 biseriate, fusoid, both ends obtuse, one-septate, constricted, 2- 

 nucleate in each cell, hyaline, 11-13 X 3-5-4-5;i*- 



Leaf-spots occur as pale discolored areas of 1-2 cm. diam., usu- 

 ally producing leaf-curl and final defohation during the summer, 

 showing under microscope mycelial development through the tis- 

 sue. Young shoots as well as bearing twigs also show irregular 

 brownish infection at the point about six inches from the end, 

 gradually drying and cracking the surface, finally causing death 

 of the tip of the shoot. 



On fruit, leaf and twig of apple. 



