ee eee 
289 
A. NEW BRITISH FRESHWATER ALGA,. 
By A. B. Renpiz, M.A., D.Sc., ano W. Wesr, Jun., B.A. 
(PiatE 399.) 
In the summer of 1896 living plants of Najas graminea Del., 
which has become naturalized in the Reddish Canal, near Man- 
chester, were received at the Museum from Mr. Charles Bailey, 
re an 
there to the Najas were short fi f a confervoid alga 
evidently allied to Cladophora, but, as the filaments were purely 
Vegetative, determination he genus was not possible. Th 
ie 
germinate. The alga, however, grew vigorously, and formed a 
ga hs mass of tan gled pediiaely branched Pate green fila- 
utumn it was observed t ming abundance 
of. tae rge dark spores, an examination of which howell it to be a 
Species be Pabegists'nh This genus was founded by Wittrock on 
the (Beast from the ‘Amazon. He subsequently wrote a mono- 
difarrioos fess P. - 
P. Vedogonia, a tropical South American species, 
a variety of which baa telat occurs in the Northern United 
have induced us to describe it as a new variety. 
The following is Wittrock’s taneleas of P. Oedogonia eo 
. Soc. Sci. Upsal. Vol. extraord. edit. 1877, p. 5 
ecimens on an average 70 p thick, with partly ian partly 
opposite branches of three degrees ; eee branches rather 
common; spores usually single, but not rarely in pairs, partly 
inclosed, partly terminal; the inclosed plete cask-shaped, on 
average 114 yp thick and 230 p long; the terminal spores sai 
shaped, with the upper end conical and the Se oe plate rounded, 
on an average 95 » thick and 214 w long. PI. s. 1-6.” 
The Reddish plant we describe as P. Out i (Mont) _Wittr. 
var. poLyspora Rendle & West fil. It differs from the type im that 
the spores are rarely single, often in pa a and not seldom aves to 
seven together. The cask-shaped terminal spores are on an average 
150 » thick and 255 » long. In some cases the terminal spores 
JOURNAL OF faite, —Vou. 37. ([Juny, 1899.] U 
