Z)Z THE MARINE BOTANIST. 



contact 5 another peculiar feature common to many 

 of the species, is that of the fresh specimens ren- 

 dering the paper on which they are spread tran- 

 sparent for the time, as if touched with oil. The 

 antheridia in this tribe are unknown, owing- to the 

 different arrangement of the spores in the g-enera 

 of the Arthrocladia, it has been deemed requisite 

 to divide the tribe into two families 5 in the first, 

 the spores are borne on slender filaments springing* 

 from all parts of the branches 5 the species of 

 Desmarestia while young are furnished with con- 

 ferva-like filaments, but no fructification has ever 

 been discovered on these plants. In the second 

 family, the spores are produced in capitula, or 

 knob-like receptacles ; but of the twenty-four 

 species known, only six are included in our Flora, 

 and none of these are common except the Des- 

 marestia. Desmarestia ligulata is an elegant plant 

 when young, and Arthroclodia villosa is a beautiful 

 plant, of a pale yellow-green, but not of fi'equent 

 occuri'ence on our shores. 



