THALLOGENS. 245 
Rhodomenia palmata, the Dulse of the Scottish coast, the Dillesk 
of Ireland, and the Saccharine Fucus of the Icelanders, is eagerly 
sought on the coasts throughout the maritime countries of Europe. 
V. OHARACE. 
The Charas are aquatic plants, composed of an axis consisting 
of parallel tubes, which are either transparent or incrusted with 
carbonate of lime, and of whorls of symmetrical tubular branches, 
multiplied by spiral-coated mucules filled with starch. They are 
among the most obscure creations of the vegetable world in regard 
to their reproductive organs, but their transparency makes them 
interesting objects of investigation, and they were the first in which 
an actual circulation of sap was observed. They inhabit stagnant 
fresh or sea waters, and live always immersed, giving out a 
foetid odour, and having a dull greenish colour. Their stems 
are regularly branched, brittle, and surrounded here and there 
by smaller branches or whorls, the axils of the uppermost whorls, 
concealing the reproductive organs, consisting of nucule, sup- 
posed to be analogous to the pistil, and a globule representing the 
anther, 
The order consists of three genera, Chara, Notilla, and Charopsis; 
the first containing on the outsides of its central tube a thick layer 
of calcareous matter, which is the result, according to Greville, of 
© peculiar economy of the plant itself, and according to Brewster, 
analogous to the siliceous deposit on Equisetum. Notilla, on the 
Contrary, is transparent, and free from all foreign matter. This 
Property seems to have recommended it as a subject for experi- 
ment. It appears that if the stem of any transparent Chara is 
examined with a good microscope, a distinct current will be seen 
to take place in every tube of which the plant is composed, 
Setting from the base of the tubes to the apex, and returning in 
C. vulgaris at the rate of about two lines per minute, and that 
. 10vement is destroyed by the application of a few drops of 
*Pinits; by pressure; or by lacerating the tube. M. Thuret’s account 
| ss the Structure and action of these plants is singularly interesting. 
uy The antherids in all the species are in the from of orange-red 
oe globules, immediately below the spore-cases. These globules consist — 
