58 SIPHONEJE. 



" On the edges of ditches, and in similar situations, it 

 frequently occurs in masses so densely matted, as to hold 

 water like a sponge, with its surface beset by erect branches, 

 which give it a very bristly appearance. In this state it is 

 well known to botanists as the C. amphibia of all modern 

 authors. Its hue is a bright green, becoming ash-coloured 

 with age. The root I have not been able to discover, and 

 the entangled mode of its growth renders it impossible to 

 ascertain the length of the filaments. These are repeatedly 

 divided with distinct patent branches, which, as before 

 mentioned, when the plant grows in shallow water, so that 

 some of them are exposed to the air, send out patent ramuli 

 of a stunted growth, from being out 'of their proper element, 

 which by their erectness give the plant its bristly appearance; 

 yet, at the same time, if whilst in this state the waters rise 

 so as to overflow the plant, their length is gradually increased, 

 and losing their erect position, they yield to the current, 

 and become the Ceramium c&spitosum of Roth ; and after 

 having thus changed, if by the subsidence of the waters the 

 surface is again exposed to the air, the filaments, of course 

 disposed horizontally, give the plant a bristly appearance by 

 again throwing out erect patent ramuli." Dittw. 



The above description of Mr. Dillwyn, is applicable, I 

 suspect, not merely to Vaucheria ovoidea, but to, perhaps, 

 nearly all the Vaucherice which dwell in shallow water. F. 

 ovoidea delights, according to Vaucher, in the purest water, 

 that of fountains for example ; and it is certainly not so 

 common as might be supposed to be, if it were the only 

 species of the genus which assumed a csespitose character ; 

 for out of the many hundred examples which I have examined, 

 I have never yet been so fortunate as to procure the plant in 

 seed. On the young, dense, and spongy tufts it is rare to 

 find capsules of any kind. 



M. Decaisne describes movements of the capsular body of 

 this species altogether analogous to those of V. clavata, detailed 

 in the Introduction. 



