CAUSE OF THE DISEASE. 13 
It has therefore seemed best to the writer to describe it as a new 
species under the name of Phomopsis malt, as follows: 
Phomopsis mali sp. nov.—Pycnidiis subglobosis, sparsis, gregariis vel in stromate, 
nigris, carbonaceis, plurilocellatis, ostiolatis. Sporulis subfusoideis biguttulatis, con- 
tinuis, hyalinis, 7-10 X 34 yw. Basidiis subulatis 20 X 2.5 ». Sporulis ordinis 
secundi filiformibus, uncinatis vel sigmoideis, attenuatis, 20-36 X 1.5 yp. 
Hab. in ramis truncisque et foliis Piri mali in Virginia, America boreali. 
[Pycnidia subglobose; scattered aggregate or in a stroma, black, carbonaceous, plu- 
rilocular, ostiolate. Spores subfusoid, containing two oil drops, continuous, hyaline, 
measuring 7 to 10 X 3to44. Basidia awlshaped, measuring 20 X 2.54. Secondary 
spores threadlike, hooked, or S-shaped, attenuate, measuring 20 to 36 X 1.5 u.] 
The vegetative portion of the fungus grows in the living part of 
the bark next to the wood, only its fruiting bodies appearing as 
minute blackish elevations, which break through the bark in diseased 
areas, giving them a pimplelike appearance. In these are contained 
the spores or reproductive bodies, which on being carried to wounds 
or small abrasions are under favorable conditions capable of germi- 
nating and producing the disease. 
Many attempts have been made to find an ascogenous form of this 
species, but so far without success. As most of the known species 
of the genus have proved to be imperfect forms of Diaporthe, the 
writer has every reason to expect that eventually a Diaporthe will be 
found to be the ascogenous form of this fungus. 
GROWTH ON CULTURE MEDIA. 
On beef-agar slants.—White cottony, with numerous flocculi, which 
later turn black, becoming pycnidia, containing spores only in rare 
cases. On this medium the pycnidia do not occur in a stroma. 
In corn-meal flasks.—Surface at first is covered with cobwebby 
mycelium, with numerous irregular raised places brownish in color. 
From these stromalike places spores are extruded in long, ropelike 
masses after one month’s time. Pycnidia are also produced singly. 
On corn-meal agar slants—Mycelium forms a delicate film over 
surface of the medium. After 45 days long ropelike masses of spores 
are produced from pyenidia, which are usually separate but are some- 
times in a stroma. 
On potato cylinders ——Growth at first consisting of fine, flocculent, 
pure-white mycelium, which later becomes dark. Finally pycnidia 
are formed, which produce spores in slender, threadlike masses. 
Pycnidia are usually separate but may be in a stroma. 
On prune-agar plates—Mycelial growth cottony; pycnidia often 
formed in a stroma, as on corn meal. Spore masses appear after 20 
days. 
1Roberts, J. W. Anew funguson the apple. Phytopathology, v. 2., no. 6, p. 263-264, Dec., 1912. 
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