232 



THE BOTANICAL MAGAZINE. 



LVol. XXIX. No. 346. 



compressed terete and branched irregularly in one plane. Each 

 branch terminates with an irregularly clefted or longitudinally 

 splitted blade, which in general outline is fan-shaped, cordate or 

 reniform. The basal part of a blade may often be more or less 

 thickened but no sorts ofriborvein is to be found in the blade. 

 The substance of blade is thin and papyraceous, and easy to 

 decay when put in the fresh water; the surface, much uneven, 

 hence labyrinthal when pressed for a herbarium specimen. 



Fig. 1. 



Fig. 1. A part of cross section of 

 blade. 



Fig. 2. A part of longitudinal sec- 

 tion of blade. 



Fig. 3. A part of cross section of 

 stem, showing about a half of the 

 thickness. 



All magnified 160 times. 



Fig. 2, 



The structure of frond may be roughly distinguished into 

 three parts, epidermal layer, cortical and medullary portion (see 

 the text figures). The epidermal layer of the blades consists of 

 single layer of small ellipsoidal cells with the longer axis per- 

 pendicular to the surface. In the stem, it becomes two or three 

 layered without any remarkable change in the shape and size 

 of the cells. In the cross sections, two or three of them— in the 



