FUNGOUS DISEASES OF ORNAMENTAL PLANTS. 25 



the leaves of La France, Fig. 1, d, which may for the lack of a better 

 term be called "bronzing", is, so far as I know, not of fungous 

 origin but probably due to a structural weakness permitting the 

 skin to become scalded by too great sun exposure. We will now 

 pass into the Carnation houses. 



Fungous Diseases of the Ccirnation. The leading fungous 

 enemy of the Carnations today is the Carnation Rust ( Uromyces 

 Garyophyllinus Schr.) This fungus, while quite new to this 

 country, is an old pest in Europe, and doubtless came to us in 

 imported stock, and within the past five years has spread through- 

 out the country. The rust can be quickly distinguished by the 

 plump gray blisters produced upon the leaves and stems. After 

 the epidermis is broken the rusty brown spores escape in great 

 numbers and the affected spots then resemble those produced by 

 other rust fungi upon grains, grasses, and many other plants. 

 Before the time of spore-formation the fungus has sent its slender 

 threads in all directions through the leaf or stem, and the plant 

 has become badly diseased. 



The work of the Carnation Leaf Spot fungus {Septoria Dianthi 

 Desm.) is easily recognized by the light brown patches upon the 

 leaf and stem. While not confined to any portion of the plant, 

 upon the stem it is most frequently found between joints. The 

 lower half of the leaf usually has more spots than the upper half, 

 and frequently a leaf bends abruptly downward near the middle 

 when a large spot has weakened it at that point. Occasionally a 

 leaf may have several bends downward and sidewise, due to as 

 many diseased spots. Over the light brown (sometimes reddish) 

 affected areas, there develop a number of minute black specks, 

 which in an old spot can be readily seen with the naked eye. 

 These specks consist of flask-shaped bodies, the walls of which are 

 formed of the interwoven threads of the fungus, and upon the inside 

 a vast number of long needle-shaped spores are produced. The 

 spores, mingled with a viscid substance, ooze from tbe small 

 opening through the wall of the flask and afterwards become 

 disseminated in various ways. In some of the fungi previously 

 mentioned, the spores have been described as produced without 

 cover upon the surface of the plant, but in the Carnation 

 Septoria the surface is finally reached by the discharge through an 

 opening. When lying upon the surface they may be moved when 

 dry by currents of air, as motes float in a sunbeam. On the other 

 hand any stream of water never so small can carry them along. 



