MYCOLOGICAL SECTION. 121 



in the grove, but may occur at several points simultaneously. The 

 evidence of these facts points to a fungus origin for the disease. 



DESCRIPTION OF THE DISEASE. 



There first appears upon either the upper or lower surface of the 

 leaves, more particularly upon the latter and upon the young shoots, 

 small, light-colored, wart-like excrescences. These excrescences in- 

 crease in number and size, the approximate ones often running to- 

 gether until the whole surface is covered, destroying of course the 

 vitality of the leaf. When young leaves are attacked they become 

 more or less distorted and their full development is prevented. The 

 top of the older warts, if one may so term them, are dark brown or 

 nearly black, due to the presence of a dense fungus growth, which 

 exhib'its under the microscope a multitude of irregularly developed 

 conidiophores, l^earing oblong, oval, one-celled conidia. (See Plate 

 VI, Fig. 3.) Such low formis as here represented are difficult to deter- 

 mine or classify, and it is just such forms which are often the most 

 injurious. Further investigations in its development will doubtless 

 reveal its true character. From what is now known it seems best to 

 place it in the genus Cladosporium. 



Upon some diseased specimens recently received from Ocala there 

 was discovered a species of Fusarium, which Mr. J. B. Ellis,* to 

 whom samples were submitted, believes to be identical with F. sar- 

 cochroum, Desm., and he expresses the opinion that the tubercles are 

 caused by the mycelium of this fungus, these being the first outward 

 manifestations of its growth. 



It may be going too far to advance any opinionat this time, but I 

 will say that after making many careful examinations of the samples 

 in hand I am disposed to think that the injury in question is occa- 

 sioned by the first fungus referred to above, the hyphse and sjjores of 

 which are present in greater or less abundance on all the more devel- 

 oped excresences. 



Remedies. — The application of the following are recommended for 

 trial as having fungicidal properties: First, a solution of bisulphide of 

 potassium, one-half ounce to a gallon of water. Second, "liquid gri- 

 son," prepared by boiling 3 pounds each of the flowers of sulpiiur and 

 lime in 6 gallons of water until reduced to 2 gallons. When settled, 

 pour off the clear liquid and bottle it for use. For use, mix one part of 

 this clear liquid in 12 gallons of water. Third, to 10 gallons of 

 strong soap-suds add about a pound of glycerine and one-half pint 

 of carbolic acid. 



These solutions should be applied in the form of a fine spray to the 

 diseased trees. As intimated, what action they may have towards 

 arresting the malady remains to be determined by experimento 



THE POTATO-ROT. 



Phytophthora infestans, De By. 

 (Plate VII.) 



There is no vegetable more widely or generally used by all classes 

 than the potato, and any disease affecting a product of such universal 

 importance is of interest to every one. Although there are a number 



* I desire to take this occasion to acknowledge the many kind favors received from 

 iilx. ElUs iu the naming of specimens of fungi suhmitted to him by me. 



