8 MICEOSCOPIC FUNGI. 



doubtless, capable of reproducing its species, and 

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

 eacli 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 iu appreciating the myriads of spores 

 which compose the orange dust produced upon one 

 infected cluster of plants of Tragojpogon. 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 ^cidium, 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 



