158 The Fungus of the Haivthorn. 



I have assumed as the type of the species the form called 

 rohustum by Blandow, and although so many named varieties are 

 brought forward, several other peculiar forms appear equally entitled 

 to the rank. Occasionally the majority of the divergent branches 

 are converted into male amentula which stud the stem throughout 

 its whole length, and render the plants conspicuous by their rich 

 purple colour. That the varieties do not depend on conditions of 

 soil is proved by the fact, that they often grow close together, or 

 even in the same tuft, but each maintaining its peculiar characters. 



V. — The Fungus of the Hawthorn — Roestelia lacerata, Tu- 

 lasne ; Mcidium laceratum, Grev. By Thomas Taylor, 

 Superintendent of the Microscopical Department of the Com- 

 mission of Agriculture, U.S.A. 



Dr. Greville, in his ' Scottish Flora,' p. 209, vol. iv., describes 

 this fungus as it was known in 1826. He says that it is found on 

 the nerves and petioles of the leaves, on the fruit, and even on the 

 young branches of the hawthorn (Cratfegus oxyacantha) in summer 

 and autumn everywhere ; and M. A. Cooke observes that it is found 

 on the under surface of the leaves and on the petioles and fruit of 

 the hawthorn, and is common from May to June in the United 

 States. 



My attention was called last year to the prevalence of this 

 fungus on the hawthorn plants on the grounds of the Department 

 during the months of July and August. This year it has also 

 appeared. I first observed its presence in the month of July, 

 although it may have appeared in June preceding. At this time, 

 September 20, the fungoid forms are decaying. Nearly every 

 variety of the hawthorn is affected, especially C. punctata and 

 C tomentosa. 



The Washington evergreen hawthorn plant G. injracantha, 

 Pers., seems not to be attacked by any species of fungus of the 

 order JEcidiacei. Judging from my observation I deem it an error 

 to suppose ^that Boestelia lacerata attacks either the branches or 

 fruit of any variety of the hawthorn. We have many varieties of 

 the hawthorn growing on the grounds of the Department, but in 

 no case have I found Boestelia lacerata on their fruit or branches. 

 This species is confined to the leaves in every instance, and the 

 petioles thus far are exempt from its attacks. On making my first 

 observations and dissections of the orange-coloured fungus, seen so 

 frequently on the branches and fruit of hawthorn bushes, I was 

 much disappointed on finding that the colour, structure, &c., of the 

 peridium and spores did not agree with that given by mycologists ; 



