Studies on the Chloroplasts of Desmids. IV. 
BY 
NELLIE CARTER, D.Sc. 
With Plates XIV-XVI. 
Contents. 
PAGE 
Xt. The Chloroplasts of Staurastrum 303 
XII. The Behaviour of the Chloroplasts during Cell-division . . . . 310 
XI. The Chloroplasts of Staurastrum. 
T HE chloroplasts of some of the smaller species of this genus are 
amongst the earliest and best known of all Desmids, since in so many 
cases their structure is quite clear from the examination of the living 
individual in the end view. Thus Ralfs (1848) figured the chloroplasts of 
Staurastrum furcigerum and others, whilst Nageli (1849) and Delponte 
(1873) also illustrated the form of chloroplast in several species. Th£ 
chloroplasts were also figured in several species by W. and G. S. West 
(1904-11), but in the case of the larger species of the genus the disposition 
of the chloroplasts is more obscure, and in many cases their structure is not 
known. It has often been assumed that these large species with very 
densely green cell-contents were provided with parietal chloroplasts, and 
Lundell (1871) separated several such species and placed them in a new 
sub-genus Pleurenterium , this being raised by Lagerheim (1888) to the 
rank of a genus. As in the case of Pleurotaeniopsis , however, such a division 
is undesirable, as explained by W. and G. S. West (1904-11), particularly 
in view of the fact that many of the species included by Lundell in Pleuren- 
terium really possess axile chloroplasts just as the majority of species of 
Staurastrum . The only species of the genus found during this work to be 
provided invariably with parietal chloroplasts was St. tumidum. 
The species examined included St. aver sum, Lund. ; St. hirsutum , 
(Ehrenb.) Ralfs; St. orbicidare , Ralfs ; St. punctidatum, Breb. ; St. aculea - 
turn, (Ehrenb.) Menegh. ; St. pyramidatum , West ; St. Simonyi , Heimerl. ; 
St. fo'rficulatum , Lund. ; St. Sebaldi, Reinsch. ; St. Manfeldtii , Delp. ; St. 
Cerastes , Lund. ; St.gracile, Ralfs ; St. margaritaceum, (Ehrenb.) Menegh. ; 
St. paradoxum, Meyen, var. longipes , Nordst. ; St. jaculiferum, West; St. 
furcigerum , Breb. ; St. Ophiura , Lund. ; St. Arctiscon , (Ehrenb.) Lund. ; 
[Annals of Botany, Vol. XXXIV. No. CXXXV. July, 1920.] 
