144 JOURNAL OF THE [December, 



before the warm spring has come, are developed eight vital 

 little objects, each of which is a slender thread-like thing. These 

 are the spores, or sporidia. Let one of them be sown on a 

 maple leaf during a warm, murky day, and it will beget its kind. 

 So it comes about that with the earliest summer sun-warmth, 

 the black housing crust cracks open, and the little cups eject 

 their sporidia and entrust them to the summer winds, which find 

 lodgment for them in the trees. 



FRUIT OF THE FUNGUS UNCINULA FLEXUOSA, 



PECK, ON LEAVES OF THE HORSE-CHESTNUT 



{.ESC UL US HIPP OCA STAN UM, L. ) . 



BY THE REV. J. L. ZABRISKIE. 

 {Read N^ovember <^th, 1886.) 



This fungus is of the family Ascomycetes, or sack-bearing 

 fungi. It is one of the Blights, of which M. C. Cooke has de- 

 scribed twenty-two species in his Hand-Book of British Fungi, 

 and of which Prof. C. H. Peck mentions forty-eight species in 

 two of his publications in 1872. 



One characteristic of these Blights is, that the mycelium of 

 the fungus, parasitic on living leaves of plants, is spread as a 

 white film on the surface of the leaf. Some species occur on 

 the under surface only, other species on both surfaces 6f 

 leaves. 



Another characteristic is, that the fruit of the fungus takes 

 the form of a nearly spherical conceptacle, from .003 to .008 of 

 an inch in diameter, usually of a dark color, and containing one 

 or more spore-sacks, or sporangia, each sporangium containing 

 two or more spores. 



A third characteristic is, that each little sphere of the fruit is 

 provided with from eight to forty or more appendages, which are 

 glassy, generally colorless, as long as the diameter of the sphere, 

 or occasionally in some species four times the length of that 

 diameter, radiating from the spherical surface like the spokes of 

 a wheel, usually, until maturity, lying flat upon the surface of 

 the leaf, and furnished at the distal extremity with a form some- 

 times of elaborate ornamentation, which is an important point 

 in the determination of species. 



The fruit here exhibited is of the genus Uncinula, so named 



