certain Monocolyledonous Leaves . 331 
Figs. 1-4. Figs. 1 a-d, Potamogeton natans, L., series of transverse sections from below 
upwards through a young leaf, from sheath, Fig. 1 a, to ‘lamina’, Fig. 1 D (X47) ; pet., petiole; 
s.a., stipula adnata . Fig. 2, Sagittaria sagittifolia , L., Figs. 2 a-g, serial sections through one 
young leaf ( x 23) from sheath, Fig. 2 a, to ‘ lamina Fig. 2 G ; a. and a'., auricles ; pet., petiole ; 
m.b., median bundle; /. x and l' . x , main lateral bundles; /. 2 and /'. 2 , bundles given off from /. x and 
/'.j to supply auricles ; Fig. 2 H, transverse section of another young leaf ( x 23) at level of detach- 
ment of auricles, vascular bundles omitted. In Figs. 2 n and 2 h the arrows indicate the 
invaginations which detach the auricles. Figs. 3 A-F, Aponogeton distachyum , Thunb., series of 
transverse sections through one leaf from below upwards (X47), vascular bundles omitted. 
Fig. 4 a-d, Hydrocharis Morsus-ranae , L., series of transverse sections through one leaf passing 
from sheath, Fig. 4 A, to ‘lamina’, p.L, Fig. 4D; pet., petiole; st. and st'., stipules; c. and c 
basal cordate lobes of ‘ lamina’ ( x 23). 
