337 
NOTES ON PONDWEEDS. 
By Atrrep Fryer. 
erhaps the character by which P. natans may be most readily 
_ separated from the other British species lies in the joint weyers 
texture as the midrib itself:—“ Lamina not extending to the base 
of the midrib, which is bare for its lower }in. Bare portion of the 
same colour as that of the upper part, and so distinguished from 
e midrib proper.”—W. H. Beeby in litt., May 5th, 1886. Prof. 
Babington is, I believe, the only author who has clearly noticed this 
jointed character of the upper leaves :—‘‘ Jointed to the stalks a little 
below the limb.’’—Bab. Manual, ed. vii., p. 871. A second, but less 
easily observe 
well as upp 
JournaL or Borany,—Vou. 25. [Nov., 1886.] 
