April, 1869.] Elliott society. 67 



APRIL 8th, 1869. 



The President in the Chair. 



Mr. W. W. Smith exhibited a specimen of Uredo Candida, with 

 the following note : 



Uredo Candida, Persoon. 



I found this specimen in the "burnt district " which is a common for the cat- 

 tle of the City. In some places the remains of old mortar and other cement 

 are washed by rains and may be seen adhering to the leaves of the herbage 

 occasionally. Associated with this is a dog-fennel which is whitened thus, and 

 the casual observer might naturally conclude that the former was likewise a 

 sprinkling of white plaster. But the appearance of organization in the regu- 

 lar coating on the leaves would induce further observation. This is a very 

 common fungus, on the Cruciferce chiefly, ( U. cruciferarum, DeCan. , Gceoma 

 candidum, Link, Schw. ) The present specimen is upon Nasturtium tanace- 

 tifoUum. It is found also on Portulacca according to Schweinitz. The Uredo 

 infests the inferior surface of the leaves, though occasionally it exhibits iiself 

 here and there on the upper. It first appears in roundish and oval tumors, 

 some on the petioles, the sori, which are beautifully white, increasing in number 

 and size until they anastomose and nearly cover the leaves. Sporidia white, 

 globose-ovoid, with obtuse apices, pretty large, with ax)parently a peUucid 

 central spot. 



Prof. McCrady read a " Critique of Darwin's Theory of Pan- 

 genesis." * 



APRIL 22d, 1869. 



The President in the Chair. 



Books Beceived, 



Boston Society of Natural History, Proceedings, Vol. XII, pp. 

 113-304. 



* See Note, page 58. 



