The Life-history and Cytology of Sorosphaera 
Graminis. 
BY 
E. J. SCHWARTZ, M.A., B.Sc., F.L.S. 
With Plate LXI. 
I N the course of some field work in the spring of 1910 I found, near 
Sevenoaks Railway Station, some grasses, the roots of which were in 
parts considerably swollen so as to give the appearance of small nodules or 
tumours. A cursory microscopical examination of these swellings revealed 
the presence of ‘ eel-worms’, which apparently were the cause of the forma¬ 
tion of the tumours. Being engaged at the time on work on Sorosphaera 
Junci , the small amount of material was laid by until the close of the 
summer of the same year, when I re-examined it with the object of ascer¬ 
taining whether the ‘ eel-worms ’ were the sole parasites or whether, as 
I thought probable, and as is so often the case, they were accompanied by 
parasitic Fungi whose presence I had perhaps overlooked during my earlier 
examination. I was pleased to find that my surmise was a correct one, 
and that the grass roots harboured a second parasite, which proved to be 
an amoeboid organism allied closely to the 5 . Jiinci mentioned above. 
This fungoid organism, which forms a new member of the Plasmodio- 
phoraceae, I propose to call ‘ Sorosphaera Graminis ’, it being a Sorosphaera 
parasitic on the roots of various grasses. The result of the study of the 
life-history and cytology of this new Sorosphaera is embodied in the present 
communication. The genus Sorosphaera , containing originally the single 
species, Veronicae , was described by Schroter in 1878 in Engler and 
Prantl’s ‘ Die natiirlichen Pflanzenfamilien ’; in this account the genus is 
distinguished from the other genera of the Plasmodiophoraceae by its 
hollow spherical collections of spores, which are enclosed by a common 
membrane. This diagnosis was subsequently modified by the present 
writer so as to include 6'. Junci , in which, although typical sorospheres are 
to be found, yet the more usual form of spore collections is of ellipsoidal or 
irregular shape. 
The cytology and life-history of S. Veronicae has been described by 
Maire and Tison ( 1 ) in the ‘ Annales Mycologici ’ in 1909, and almost simul- 
[Annals of Botany, Vol. XXV. No. XCIX. July, 1911.] 
