56 KiijroaT of thb Botanist of the 



observed for the first time upon the carnation rust. In a green- 

 house at Flatbush, Long Island, it has been found on the variety 

 Gen. Maceo; and in each of three different greenhouses at Geneva 

 on several different varieties. While not naturally very effective 

 as a check, by the use of artificial cultures or inoculations some 

 benefit may be derived from its presence. 



THE PARASITE. 



{Darluca filinn (Biv.) Cast.). 



This fungus is related to the Septorias and Phomas familiar to 

 florists through the diseases they produce. In some way this 

 fungus has become adapted to living upon the tissues of other 

 fungi instead of deriving its nourishment solely from the host 

 plant. 



The presence of Darluca is best determined with the micro- 

 scope. But in cases where the rust is badly infested, the dwarfed 

 and evidently crippled development of the rust pustules indicates 

 that something is wrong. At times there are dead Jireas, in which 

 are scattered a number of very fine black specks; these are the 

 pycnidia of the Darluca. In other cases the infested area is 

 nearly black, and the pycnidia are abundant. A third type of 

 infestation is visible only with the aid of the microscope; in this 

 the pycnidia are scattered amiong the spores in the infested pus- 

 tules, which otherwise appear normal. In any case the presence 

 of the Darluca, as of the rust, is shown externally only when it 



reaches maturity and produces spores. 



The spores of Darluca are two-celled and colorless. They are 

 developed within pycnidia or flask-shaped fruit-bodies, which 

 may be nearly spherical, or much elongated. When a ripe pycni- 

 dium is moistened, the spores are expelled in a thick rope, which 

 holds together by the gelatinous covering of the cell walls of the 

 spores. 



The pycnidia are formed from a cluster of interwoven vertical 

 branches of hyphae. As the mass thus begun develops, a cavity 

 is formed at the center, which enlarges until only a thin mem- 

 brane is left as the pycnidial wall. From the interior of this 



