CHLOROPHYCEA 123 
The Thallus—There is hardly any type of habit 
assumed by the higher terrestrial plants that does 
not find itself represented in this singular genus. 
There are species named from their resemblance to 
mosses, club-mosses, cacti, yews, 
are of extremely simple form. 
This differentiation is not con- 
fined to the green assimilating 
shoot, but extends to the root- 
system with its creeping rhi- 
zome-like extensions. The 
plants frequently attain con- 
siderable stature, and are in 
most cases of remarkable 
beauty. It has been said? 
that “Nature appears to have 
executed in the forms of this 
genus a tour de force in ex- 
hibiting the possibilities of 
the siphoneous thallus — in 
showing that it is possible for 
a unicellular organism to dis- 
play the varied beauties of 
outward form characteristic of 
highly-organised types; to at- 
tain by means of a lattice- 
etc., etc., while others 
Fic. 31.—Caulerpa cactoidrs 
var. gracilis one-third natural 
size. 
work of crossbeams within the cell-body that mechan- 
ical support effected by transverse septa and separ- 
ate, differentiated cellular structures for other Algee 
and for the higher plants.” 
1 Trans. Linn. Soc. Bot., 2 ser., vol. iii, part 4., p. 207. 
