CHLOROPHYCE^ 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, etc., etc., while others 

 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 1 

 that " Nature appears to have 

 executed in the forms of this 

 genus a tmtr 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- 

 work of crossbeams within the cell-body that mechan- 

 ical support effected by transverse septa and separ- 

 ate, differentiated cellular structures for other Alga? 

 and for the higher plants." 



1 Trans. Linn. Soc. Bot., 2 ser., vol. iii., part 4, p. 207. 



