On Glaucocystis Nostochinearum, Itzigsohn. 
BY 
B. MILLARD GRIFFITHS, M.Sc. 
With Plate XIX. 
LAUCOCYSTIS NOSTOCHINEARUM , Itzigs., is a unicellular 
vJT solitary alga found generally in Sphagnum-bogs. It is ellipsoidal in 
form and measures from 30 to 45 /x in length, and from 18 to 25 /x in breadth. 
It has a chromoplast consisting of a number of strongly recurved radiating 
bands of a blue green colour. It reproduces by the formation of two, 
four, or eight daughter-cells within the mother-cell. 
The systematic position of the organism has been doubtful. Chodat 
placed it in the Protococcaceae owing to its resemblance to Oocystis (vide 
Oltmanns, ’ 04 ). Oltmanns can find no certain place for it, but refuses 
to put it in the Protococcaceae owing to its blue-green colour. West (’ 04 ) 
classifies it among the Cyanophyceae (or Myxophyceae). He divides the 
whole group into Glaucocystideae and Archiplastideae, and therefore places 
Glaucocystis outside the rest of the Cyanophyceae. The difficulty of assign¬ 
ing it to a definite group is intensified by conflicting evidence regarding 
its nucleus. Lagerheim states that the nucleus is merely a vacuole (Hiero¬ 
nymus, ’ 92 ). Hieronymus describes a perfectly definite nucleus containing 
a body resembling a nucleolus. 
I found the organism in considerable quantities at the beginning of the 
year 1910, and with this material at my disposal have carefully examined 
the nucleus with a view to discovering its exact nature. The investigation 
was suggested by Professor G. S. West in order to obtain further information 
concerning its cytology with a view to determining the systematic position 
of the organism. The results show that Glaucocystis is one of the Cyano¬ 
phyceae, but with a nuclear structure of much greater definiteness than 
is found in the rest of the group, and possessing many features that make 
it almost comparable with the more highly elaborated nucleus of higher 
plants. 
The organism occurred in a small permanent surface-water pool near 
Kidderminster, Worcs., among the lower portions of a dense growth 
of Fontinalis antipyretica. It was found at all seasons of the year, but 
most plentifully in the colder months. The pool was not more than a few 
[Annals of Botany, Vol. XXIX. No. CXV. July, 1915.] 
