HYDRODICTYON AFRICANUM, A NEW SPECIES 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 166 
SHIGEO YAMANOUCHI 
(WITH SIX FIGURES) 
The genus Hydrodictyon, as found in Europe, North America, 
and Asia, has been represented by a single species, H. reticulatum 
(L.) Lagerh. (H. utriculatum Roth.). Its normal life history, 
external appearance, habitat, and size at maturity are quite familiar 
to students of algae. Although little is known of the cytology of 
the zoospores and gametes, and the germination of the resting 
spores and polyeders, the general organization, with some details 
of the vegetative nuclear divisions and methods of forming spores 
and starch, have been described by VAUCHER, BRAUN, PRINGSHEIM, 
ARTARI, KLeBS, TIMBERLAKE, and HARPER. 
In April 1912, shortly after Professor CHAMBERLAIN’S return 
from an extensive trip through Australia and South Africa, some 
soil was sent to him by Miss Eprrn STEPHENS of the South African 
College. The soil was secured on the Valkenberg Vlei, near Cape 
Town, and was supposed to contain spores of the liverwort Riella. 
Some individuals of Riella appeared in the culture, but in addition 
to these there appeared a new species of Hydrodictyon, which we 
shall call H. africanum. The following description is based upon 
the material from this culture. 
Early in May there appeared on the bottom of the tank, just 
above the surface of the soil, a number of green spherical bodies 
of barely recognizable size, which had the general aspect of Boiry- 
dium. As growth progressed, the spherical bodies, instead of being 
groups of solitary cells, were seen to be connected into nets. The 
nets are made up of 60 or more globular cells which form irregular 
meshes, arranged in hexagons, heptagons, or octagons, or some 
times simply in broken chains. The nets grow rapidly. Each 
cell does not grow into an ellipsoidal cylinder as in H. reticulatum, 
but remains spherical or oblong. The cells have remarkable 
Botanical Gazette, vol. 55] (74 
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