ALGE 79 
tween the cells. Parthenogenesis is probably a not in- 
frequent phenomenon, and marks the extreme point of 
divergence from the typical green alge. 
Both Phzophycee and Rhodophycee reach a far 
higher degree of specialization of the plant body than 
is ever met with among the Chlorophycex, but there 
is no evidence that either group has given rise to any 
higher types of plant structure than exist at present 
within the classes themselves, the most specialized of 
the existing forms representing probably the highest 
expression of these peculiar structural types. 
The assumed relationships of the main group of Alge 
may be illustrated by the following diagram : — 
Mosses 
a 
Confervacess 
8) Conjugate 
5 Siphoness 
8 rotovoccacess wae 
8 
a 
Py se 
ny 
ee 
SS 
‘inoflagellata Volvociness 
Brown Alga Green Algge 
