Blackman and Tansley, 
A REVISION OF THE CLASSIFICATION OF 
THE GREEN A LG/E 
BY 
F. F. Blackman, 
University Lec-turer in Botany , Cambridge. 
AND 
A. G. Tansley, 
Assistant Professor of Botany, University College, London, 
(Continued from page 24 .) 
IV. Phacoteae. 
Body as in Chlamydomonadeae, but with a thick solid wall 
which at the escape of daughter individuals separates into two 
valves (sometimes obvious during vegetative phase). 
Reproduction as in Chlamydomonadeae. 
Genera. 
1 . Pteromonas. Seligo. 
Body with closely adherent wall projecting laterally as 
two wings. 
2 . Coccomonas. Stein. 
Body ovoid with hard, outstanding, often four-angled 
wall. 
3 . Phacotus. Perty. 
Body ovoid with a sculptured calcified outstanding lens¬ 
shaped wall, consisting of two loosely-connected 
valves, which separate at escape of daughter 
individuals. 
[Among the unicellular motile forms two interesting but apparently 
isolated and little-known types should be mentioned. Gloeomonas, 
Klebs, has a body of the Chlamydomonas-type , but has numerous 
parietal rounded or elongated chromatophores and no pyrenoids; also a 
mucilaginous investment, outside and distinct from the ordinary cell- 
wall. Vegetative division as in Chlamydomonas. Gamogenesis unknown. 
Cylindromonas, Hansgirg, has an oblong-cylindrical body with a thin 
cell-wall and bearing a single flagellum at the anterior end ; there are 
two star-shaped chromatophores, each with a central pyrenoid, and 
enclosing a nucleus between them, as in the Desmid Cylindrocystis. 
Vegetative division into 2-4 daughter cells within the mother cell-wall.] 
V. Volvoceae. 
Body a motile ccenobium of Chlamydomonadine cells, 
sometimes united by protoplasmic threads, and nearly always 
embedded in a mucillaginous investment, through which the 
flagella project, and by their combined lashing give the ccenobium 
the power of locomotion. Cells all equivalent and capable of 
division to reproduce the species, or in the highest forms 
differentiated into ( 1 ) purely vegetative cells which have lost the 
power of division and ( 2 ) reproductive cells which alone can 
divide to propagate the species. 
