Thus simple forms included in the Heteroconteae, Chlorophyceae and Phaeophyceae show an obvious connection with the Flagellatae; the Peridineae may be regarded as a further developed branch; the Conjugatae and Diatomaceae cannot be directly connected; the origin of the Rhodophyceae is also obscure; while the Characeae are an advanced and isolated group (see ALGAE).
Again, while Conjugatae may be shut out from Chlorophyceae as an independent group co-ordinate with them in rank, the Characeae constitute so aberrant a group that it has even been proposed to raise them as Charophyta to the dignity of a main division co-ordinate with Thallophyta.
Among Chlorophyceae it is often the case that the oospore on germination divides up directly to form a brood of zoospores.
Some Chlorophyceae are terrestrial in habit, usually growing on a damp substratum, however.
In the case of the freshwater algae, however, belonging to the Chlorophyceae and Cyanophyceae, although they required to be immersed during the vegetative period, the reproductive cells are often capable of resisting a considerable degree of desiccation, and in this condition are dispersed through great distances by various agencies.
Characeae are separated from other Chlorophyceae by Ulvaceae that there is any pretension to the formation of a true a long interval, and present the highest degree of differentiation of parenchyma within the limits of the Chlorophyceae.
Instead of a single relatively large The Chlorophyceae excel all other groups of algae in the magnitude and variety of form of the chlorophyll-bodies.
A census of the Chlorophyceae is furnished below: I.