120 THE MAREMMA. 



volcanic tufa, which, when sufficiently softened, forms a 

 pasturage, on which feed large herds of cattle. It con- 

 tains the finest pastures of Italy, -on the soil of which are 

 commingled the ordure of cattle and the disintegrated 

 tufa. The former is known to be a favorite growing 

 ground of the fungi, and the latter, I shall now proceed to 

 show, is even better calculated for the same offices. 



According to M. Roques, the fine mushroom, polyporus 

 tuberaster, of the Italians, grows in the environs of Naples, 

 upon a species of volcanic tufa, very porous and of an ar- 

 gillo-calcareous nature. In the pores of this stone, is de- 

 posited the matrix of the plant, from which, when moist- 

 ened and shaded, grow up vast mushrooms, four or five 

 inches high, and eight or ten inches broad. These stones 

 are sent to France and England, where they are used as 

 in Italy, for the production of mushrooms. The English 

 Philosopher, Boyle, first described this stone, under the 

 title of Lapis Lyncurias ; "which," to use his own lan- 

 guage, "rubbed, moistened, and warmed, will, in a very 

 short time, produce mushrooms fit to be eaten." Old John 

 Hill, who wrote, a century ago, a volume on Materia Me- 

 dica, published a book entitled "Lapis Fungifer," in which 

 he describes a stone of this kind, in the possession of Lady 

 Stafford. It was a hard, heavy mass, of an irregular shape, 

 and granulated texture, like shagreen leather. This formed 

 the nidus for the perennial root of a fungus superior to 

 common mushrooms. One of these fungi weighed, accord- 

 ing to Hill, two pounds two ounces, and measured six and 

 a-half inches on the head. The Doctor presumes that the 

 Lapis Violaceus of the Germans is of a similar nature. 



The Neapolitans bring the tufa used in their horticul- 

 tural processes, from Calabria, where are found the sam- 

 ples of that volcanic earth, of the finest quality. It is 



