270 FUNGI. 



it makes to the soil is trivial and of slow addition. There is nothing 

 more remarkable in the tribe than the occasional slow growth and 

 long persistency of individual plants. 



Again, if the exposed surface is earthy, Lichens neither begin nor 

 forward the work. A bank, that came under frequent observation, 

 had been completely denuded of its covering to the depth of several 

 feet in spring. In the September following, I found the surface of this 

 bank partially covered with a various vegetation of the commonest and 

 coarsest plants. Here is a list of them : White-Clover, Dandelion, 

 the common Mallow, Henbane, Hemlock, Chickweed, Rib-grass, 

 Black Medick, Fumitory, Ragweed, Grundsel, Sow-thistle, Horse- 

 Gowan, the common Thistle, Polygonum avicvdare, the Nettle, the 

 Poa annua, and a moss in patches without fruit, probably a Tortula! 

 This catalogue was made on the spot, and is a complete one for a 

 surface of more than 20 feet in length. The coarser plants are now 

 gradually disappearing before the encroachments of some grasses that 

 have been subsequently developed. 



VI. Fungi. 



AGARICUS INVOLUTUS. 



Hymenomycetes. 



Meadow Species. Agaricus fragrans. 



Agaricus procerus. cyathiformis. 



personatus. gambosus. 1 . 



muralis. tener. 



ericetorum. Georgii. 



1. = Ag. graveolens, Fl. Berw. ii. p. 166. See Ann. Nat. Hist. vi. p. 355. 



