2?4 Liliputian Enemies. 



of plants, but is less destructive than some of its congeners. The old 

 genus included the black-spored species, which have since been separated 

 under distinct names. As now limited, Uredo includes the yellow-spored 

 forms, more or less circumscribed in spots or blotches. On the under side 

 of the leaves, generally, of many plants, may be seen these yellow spots, 

 sometimes scattered irregularly, and sometimes confluent over the whole 

 leaf. They germinate within its tissues, the fungus being then merely 

 branching threads, termed mycelium, which, at a certain stage of growth, 

 give off from their ends little globules, which are individual cells, that 

 fall away at maturity, and constitute the reproductive germs. They burst 

 through the epidermis, and appear on the surface ; and, as the threads 

 of the mycelium continue to give off these terminal cells, they soon cover 

 the leaf with a dense mass which looks like dust. Under a high power 

 of the microscope, they appear as little pellucid globules- Their germi- 

 nation consists in a protrusion of their inner membrane from different 

 points of the surface, which grows into similar branching threads to those 

 which first gave them birth. This is the whole plant, a branching thread, 

 and a terminal cell for a germ. If any one will hunt among the leaves of 

 the low wild blackberry, he will find the under surface covered with a splen- 

 did orange-colored felt. This is the mass of spores of Uredo nitens. The 

 winter-green {Fyrola rotundifolia) is infested with another species, Uredo 

 PyrolcB, which appears in round spots. Another species is found on 

 grasses and corn : in fact, these yellow rusts occur on a vast number of 

 plants of all families. 



Nearly identical with Uredo is the genus ^cidiii/n, differing in having 

 a surrounding membrane, distinct from the epidermis of the plant it infests, 

 which breaks at the apex, and shows itself in a little lacerated margin which 

 radiates irregularly around the mass of spores in the centre. It occurs on 

 a great variety of plants. The common barberry will furnish specimens 

 every summer. The leaves are spotted with a blistery pustule ; which 

 will be found, on close examination, to be dotted with little yellow 

 points made up of a mass of yellow spores, contained in a membranous 

 pocket, irregularly jagged at the edges. This is yEeidium Berberidis. 

 Gooseberries are attacked by A. Grossularice. An allied genus, Roestclia, 

 is found on pomaceous plants. We have seen a young quince completely 



