8 MICROSCOPIC FUNGI. 



doubtless^ capable of reproducing its species^ and 

 if we compute 2^000 cluster-cups as occurring on 

 eacL. leaf^ and we have found half as many more on 

 an ordinary- sized leaf, and suppose each cup to 

 contain 250^000 spores^ which again is below the 

 actual number_, then we shall have not less than 

 five hundred millions of reproductive bodies on 

 one leaf of the goatsbeard to furnish a crop of 

 parasites for the plants of the succeeding year. 

 We must reckon by millions^ and our figures and 

 faculties fail in appreciating the myriads of spores 

 which compose the orange dust produced upon one 

 infected cluster of plants of Tragopogoii. Nor is 

 this all^ for our number represents only the actual 

 protospores which are contained within the peridia ; 

 each of these on germination may produce not 

 only one but many vegetative spores^ which are 

 exceedingly minute, and, individually, may be 

 regarded as embryos of a fresh crop of cluster- 

 cups. And this is not the only enemy of the kind 

 to which this unfortunate plant is subject, for 

 another fungus equally prolific often takes posses- 

 sion of the interior of the involucre wherein the 

 young florets *are hid, and converts the whole into 

 a mass of purplish black spores even more minute 

 than those of the JEcidiiim, and both these para- 

 sites will be occasionally found flourishing on the 

 same plant at the same time (plate V. figs. 92 — 94). 

 Naturally enough, our reader will be debating 

 within himself how these spores, which we have 



