154 de Fraine.—The Seedling Structure of certain Cactaceae. 
tubercle-strand U bifurcates; its halves pass outwards and fuse with the 
seed-leaf-trace, forming the second bundle (Fig. 15, and Diagram n, 
c ‘<% 
t, 
t z 
1 
!■ 1 
A 
z Cl. 
w 
3 Cz. 
4 
Diagram ii. Echinocactus Ottonis, Series 3. 
Figs. 1-4). In this seedling we thus have a further example of a tubercle- 
trace acting in the manner usually associated with a cotyledonary bundle. 
Echinocactus Ottonis , Series 1, shows an interesting feature in its 
Diagram 12. Echinocactus Ottonis, Series 1. 
