300 



GONIDIA. 



PART II. 



marrow, which, is the origin of fructification, consists of 

 lax, detached, branching rows of elongated cells and 

 gelatinous matter. These branches of cells spring up 

 from a fourth layer, which is the base of the plant. It 

 is of a strong, firm, and tough nature, composed of inter- 

 laced filaments and is often ribbed on the under-side. 

 White fibres fix the base of the plant to the surface on 

 which it is spread ; they are the remains of a mycelium 

 or matted mass of fibres, from whence lichens spring, 

 which vanishes when the plant is full grown. 



Globular bodies of vegetable green called gonidia, 

 like those at the base of fig. 39 a, are arranged in 

 regular parallel rows, and placed between the surface 



-SOQQQJ 



Fig. 38. a, Sporopodium Leprieurii, ascus ; 6, Coccocarpia smaragdina, section ; 

 c, Lecanora affinis, section. 



and the base of the lichen, as in fig. 38 b and c ; they 

 are said to proceed from the medullary layer, though Mr. 

 Berkeley has seen them springing from the threads of 

 the mycelium of Parmelia parietina. The gonidia find 

 their way to the air through rents in the surface of the 

 plant, and are washed off by the rains, after losing a little 

 of their green colour. When they germinate they only 

 produce a facsimile of the mother plant, as buds do in 

 the highest classes. But according to the microscopic 



