344 
A rber 
On the Nature of the ‘ Blade ’ in 
Figs.' 22-29. Figs. 22 Aristolochia Clematitis, L., series of transverse sections of a single 
leaf from apical bud ( x 23) ; Fig. 22 A, attachment of sheathing base, j., enclosing axillary bud, b., 
to axis, ax. ; c. and c' ., bases of cordate lobes of lamina; Fig. 22 B, petiole,/^. ; Figs. 22 c and D, 
lamina. Figs. 23 a-d, Populus sp., series of transverse sections through a very young leaf ( x 23) ; 
Fig. 23 A, sheathing base ; Fig. 23 B, stipules, j. and s'., detached from petiole, pet . ; Figs. 23 c-e, 
development of lamina. Figs. 24 A and B, Polygonum amphibium , L. Fig. 24 A, transverse section 
of apical bud passing through three leaves, and f. 3 ( x 23) ; fxS., sheath of first leaf ; m.b., 
median bundle of first leaf ; f. 2 lam., lamina of second leaf ; m.b. 2 and i.b. 2 , median bundle and inverted 
bundle of second leaf; f 2 o., ochrea of second leaf; f. s lam., lamina of third leaf ; m.b, 3 and i.b. 3 , 
median bundle and inverted bundle ofthird leaf; Fig. 24 B,leaf 1 at a higher level ( x ochrea; 
