CLUSTEE-CUPS. 13 



in size from less than one-twelfth, of an inch to half 

 an inch in diameter. It is found on several species 

 of Ranunculus, as R.acris, hulhosus, and repens, but 

 most commonly on J^. Jicaria. The leaf is thickened 

 at the spot occupied by the parasite, and generally 

 without indication on the opposite surface. Some- 

 times one spot, at others several, occur on the 

 same leaf. The peridia are densely crowded to- 

 gether, often arranged in a circinate manner, i.e., 

 like a watch-spring, or the young frond of a fern. 

 The spores are orange, but slightly varying in tint 

 on different species of Ranunculus (plate II. figs. 

 12 — 14). One of the smaller clusters, when col- 

 lected before the spores are dispersed, or the teeth 

 of the peridium discoloured, mounted dry as an 

 opaque object, makes a very excellent slide for an 

 inch or half-inch objective ; and the same may be 

 said of many others of the same genus. 



Less common than the foregoing is the species 

 of ^cidiiim which attacks the violet. The sweetest 

 of flowers as well as the earliest, in despite both of 

 its odour and its humility, becomes a victim to one 

 or more of the ubiquitous race of fungi. Thickened 

 spots at first appear on the leaves ; the petioles, or 

 flower stem, or even the calyx, become swollen 

 and distorted ; and at length the cluster-cup breaks 

 through. The spots on the leaves upon which the 

 peridia are scattered are yellowish, generally larger 

 than the clusters on the pile- wort, and seldom with 

 more than one spot on each leaf. The peridia, or 



