26 .MASSACHUSETTS HORTICULTURAL SOCIETY. 



In case of plants under glass where watering is frequent it is likely 

 that the wet method of transportation is most active, especially if 

 the hose is used with considerable force. A strong spray playing 

 upon a healthy plant through one affected with the Leaf Spot 

 would be quite sure to carry along an abundance of the spores 

 and leave them in drops of water in a suitable condition for 

 germination. The prevalence of the disease at the base of the 

 clasping leaves of the carnation may be due to the fact that the 

 water is held there longer than elsewhere. 



The Carnation Anthracnose (species not fully determined) is a 

 third fungous trouble frequently met' with, and may be character- 

 ized by sharp-pointed black hairs arranged in microscopic rosettes 

 upon the surface of stem or leaf. The spores are borne upon the 

 tips of radiating threads intermingled with the black hairs. This 

 fungus is fond of moisture and is most frequently found upon the 

 lower stems and leaves that lie upon the earth or are matted 

 together. A whole branch may be destroyed by the anthracnose 

 that has affected its base and checked the flow of sap. 



The Leaf Mould {Heterosporium echinulatum Berk.) is a 

 fourth fungous trouble of the Carnation, which is easily distin- 

 guished by its forming circular spots in the foliage varying from a 

 small dot to a ring extending across the whole leaf. At first the 

 spot is of a pale ashy color covered with a dense mould, but 

 changes with age to a dark brown. This change of color is due to 

 the maturing, upon the minute branches of the mould, of many 

 spores. When fully ripe the spores are covered with microscopic 

 prickers. In its worst form a plant, and particularly the younger 

 portion, will be literally covered with the blending circular spots 

 of this fungus. 



The last fungous disease of the Carnation to be mentioned 

 before passing on to the violet houses is of bacterial origin. The 

 germs of this disease are exceedingly small, there being no thread- 

 like structure or spores as met with in the fungi previously 

 mentioned. Attention is attracted to tlie victim by the manifest 

 lack of vigor, and the consequent failure to produce the usual 

 number of blooms. If a leaf of a diseased plant is held up to 

 the light many somewhat transparent dots will be observed, vary- 

 ing from a mere point to specks an eighth of an inch in diameter. 

 These dots are the starting points of the bacteria which, swarming 

 in the cells of a leaf, destroy the ordinary green substance 

 (chlorophyll), and finally the leaf becomes discolored and lifeless. 



