Studies on the Chloroplasts of Desmids. I. 
BY 
NELLIE CARTER, M.Sc. 
With Plates XIV-XVIII. 
Contents. 
PAGE 
I. Introduction . . . .215 
II. General Characters of the 
Chloroplasts . . . .219 
III. The Chloroplasts of Netrium . 227 
IV. The Chloroplasts of Closterium . 228 
I. Introduction. 
Historical. 
T HE first figures of Desmids which give one any clear idea of the nature 
of the cell-contents were those of Ralfs (1848). Although Ralfs did 
not attempt to indicate the form of the chloroplast in the larger species of 
Euastrum and Cosmarium, yet from his figures of such genera as Desmidium, 
Closterium , and Staurastrum, a fairly good idea of the structure of the 
chloroplasts in these forms can be obtained. 
Nageli (1849) also figured typical chloroplasts of the genera Pleurotae- 
nium, Closterium , Netrium, Staurastrum, and Cosmarium. 
De Bary (1858) described in general the chloroplasts of the group, and 
made a statement to the effect that all Desmids, with the exception of species 
of Pleurotaenium and Spirotaenia, have axile chloroplasts. This is by no 
means true, however, since parietal chloroplasts are known to occur in many 
other genera besides these two. De Bary also described in more detail 
some of the simplest types of chloroplast found in each genus, and gave an 
account of the behaviour of the chloroplasts in a few genera during cell- 
division. 
Lundell (1877) attempted to subdivide the genera Cosmarium and 
Staurastrum according to the disposition of the chloroplasts, and instituted 
[Annals of Botany, Vol. XXXIII. No. CXXX. April, 1919.] 
R 
PAGE 
V. The Chloroplasts of Tetmemorus 236 
VI. The Chloroplasts of Euastrum 237 
VII. The Chloroplasts of Xanthi- 
dium ...... 245 
VIII. Summary ..... 248 
