THE 
NEW PHYTOIiOGIST. 
Vol. XV, Nos. i & 2. Jan. & Feb., 1916. 
[Published March 25th 1916]. 
ON THE STRUCTURE AND ORIGIN OF 
“CLADOPHORA BALLS.” 
By Elizabeth Acton, M.Sc. 
[With Five Figures in the Text]. 
T N the early part of the year I had an opportunity of examining 
some “ Cladopliora balls ’’which had been collected from Loch 
Kildona, S. Uist, and several observations were made which had 
not previously been recorded. Prof. G. S. West suggested that, 
as these balls are not very well known in this country, a paper 
describing them might be of general interest. 
“ Cladophora balls ” are of frequent occurrence in certain lakes 
in Scotland and Ireland. They are also widely distributed in other 
parts of Europe and their origin and structure have been carefully 
investigated by several authors. In 1902 Brand 1 published a paper 
dealing with the various members of the Aegagropilas and the 
anatomy of the single plants; the literature on the subject is also 
fully discussed. A few months later a paper appeared by 
Wesenberg-Lund 2 on Aegagropila Sauteri of Lac Soro; this is 
devoted almost entirely to the origin and mode of formation of the 
ball-like stages which appear floating on the surface of the lake in 
the months of April and May. I am chiefly indebted to the works 
of Brand and Wesenberg-Lund for my knowledge of the Cladophora- 
Aegagropilas, but mention will be made later of other papers 
which have been consulted. 
The “ Cladophora balls ” belong to the group of plants known 
as Aegagropilas. In the general sense this term has been used to 
describe loose masses of algae rolled into irregular balls by the action 
of the waves and currents. In its systematic sense it has been 
1 F. Brand. “ Die Cladophora—Aegagropilen des Susswassers.” 
Hedwigia, Bd. 41, 1902. 
2 C. Wesenberg-Lund. “ Sur les Aegagropila Sauteri du Lac de Soro.” 
Bull. Acad. roy. des sciences et des lettres de Danemark, 1903. 
