216 TRANSACTIONS OF THE ILLINOIS 



wheat rust, and known as Puccinia helianihi, Sclnv. The leaves, often 

 both sides, are quite brown from the numerous pustules. They wither 

 upon the stem, and finally break to pieces, scattering far and wide the 

 reproductive germs. 



Red cedar trees bear upon their branches reddish coppery-colored 

 balls, which at a certain time in the spring, during rain, give rise to 

 numerous gelatinous, sprawling, yellow appendages, then very conspicu- 

 ous, and often thought to be the true fruit of the tree. This fungus, 



{ Gymnosporangium , ,) is, different as it appears, a near relation to the 



Puccinia of the wheat, the spores being borne in the gelatinous arms. 

 The mycelium (threads) appear to be perennial, robbing the bark and 

 young wood of the prepared sap, and storing up the nutriment in these 

 galls for its own fruiting. The tree does not immediately perish, but is 

 evidently enough weakened, and as the robber increases from year to 

 year, if allowed to do so, the resources are at length exhausted, and death 

 ensues. If, however, the balls are gathered and burned, the difficulty is 

 obviated. 



The leaves of beans, especially of the pole varieties, were seriously 

 injured by a rust which appears as minute black specks, pretty thickly 

 distributed, generally upon the under surface. The leaves appear sickly, 

 and ultimately wither away, remaining attached to the stem until broken 

 off. The black specks are composed, as is so often the case, of spores. 

 Under the microscope these are seen to have a long stem, terminated by 

 an undivided, rounded head (spore) with a blunt apical appendage. No 

 less than four kinds of " fruit" is known to be produced by this fungus 

 {Uromyces appendiculata), but in this case the one described is the only 

 kind found. These doubtless are the winter spores, which by their 

 germination start the series the following season. Here again burning 

 affected plants might prevent ravages another year. 



Cottonwood trees drop their leaves sometimes very early in the fall, 

 and it does not require very sharp looking to discover thickly sprinkled 

 over, or under, the surface orange colored dots. Willows have the same 

 thing happen to them. But for the injurious effects of the parasite here, 

 these trees would hold their leaves much later, and profit thereby. As 

 ornamental trees, this premature shedding of the leaves is a decided dis- 

 advantage. Two forms of spores are produced, the first kind maturing 

 in late summer and making up the orange dots observed ; the second, 

 curiously enough, are developed after the cold weather sets in, while the 

 dried leaves are lying upon the ground. If such leaves are examined 

 during winter they will be seen as thickly sprinkled with dark brown 

 dots as the green ones were with orange. Each dot, though barely visible 

 •to the eye, contains some hundreds of oblong spores, packed as close as 

 kernels of corn upon its cob, ends outward. These germinate in the 

 spring, and being carried in the air, gain access to the young leaves. 

 Before it was known that the two kinds of spores belonged to the same 

 fungus, the first sort was classed, with its congeners, under the generic 

 name of Lecythea, and the latter was, as it still is, known as Melamspora 



