V 



INTRODUCTION TO CRYPTOGAMIC BOTANY. 



151 



parts of the same thread. In one Indian species the jelly is 

 so abundant that the dry specimens present a sort of net-work 

 with compound threads. Unfortunately I have no informa- 

 tion as to its condition when fresh. The most singular point, 

 however, in these plants, is the mode of formation of the spores. 

 These arise from the intermixture of two neighbouring endo- 

 chromes, or from the division of one primitive endochrome 

 into two, and very rarely indeed in several successive articula- 

 tions. In this latter case, the divided portion of the endo- 

 chrome, which did not bear a spore, swells, increases in length, 

 is itself divided, and the posterior half becomes fertile, and 

 the process may be repeated till a chain of spores is formed.* 

 The endochrome in the fertile half-cell, whether mixed with 



Fig. 38. 



a. Threads of (Edogonium concatenatum, Hass., showing the origin of 

 the spore from the division of one of the articulations into two cells. 



h. Thread of (Edogonium crassum, showing the protrusion of the 

 inner membrane before disarticulation. 



c. Threads of (Edogonium hexagonum. 



All magnified from specimens in my herbarium. 



that of the neighbouring cell or not, contracts into a globular 

 or elliptic mass, acquires a distinct envelope, most probably 

 after impregnation, and thus forms a spore. In some instances 

 these spores are perfectly quiescent, but in others they have 



* Thwaites in Ann. of Nat. Hist., vol. xvii. p. 333. 



