286 LETTER XXV. 



stance, such as the Truffle, and finally arrive at their 

 most perfect state in the Agarics, or Mushrooms, 

 that we eat, and in the Boleti, which grow like huge 

 fleshy excrescences on the trunks of trees, or project 

 from their trunks in long and ugly lobes, which have 

 in one case been compared to the claws of some gi- 

 gantic demon. 



Instead of occupying you about the particulars of 

 all these matters, I shall content myself with explaining 

 to you the nature of the developement of one of the 

 most completely formed fungi, the veiled Agaric (Aga- 

 ricus volvaceus). In the beginning this plant is no- 

 thing but a thin layer of cobweb -like matter, spread- 

 ing among old tan ; by degrees, on the surface of the 

 cobwebs appear little protuberances of a whitish 

 colour (Plate XXV. 3. jig. 1.) ; they gradually 

 lengthen, and acquire a sort of stalk, and up to a 

 particular period consist of only a fleshy mass of 

 fibres and minute cells ; if they are cut through 

 at that time in a perpendicular direction {fig. 2.), 

 they present one uniform face. But in a short time 

 a minute cavity is formed in the fungus at the thicker 

 end (fig- 3.), within which a sort of cap is gradually 

 elevated upon a stalk {fig- 4.) ; the cap and stalk 

 keep progressively enlarging {figs. .5, 6, 7» 8-)j ^^^ 

 stretching the skin within which they are enclosed, 

 till at last the skin cracks {fig, 10.) ; the cap and its 

 stalk rapidly enlarge, and tear a way through the 

 ^\.m {fig, 11.) and at last burst forth into light, a 

 perfect mushroom {fig. 12.), with numerous cinna- 

 mon brown gills or lamellae radiating from the 



