i75 
the Embryo and Seedling in the Gramineae. 
the coleoptile. The internode contains a circle of twelve traces (Diagram I, 
Text-fig. 17): seven derived from the second leaf (m ; l v / 2 , 4 ; l\ y l\, l'^), and 
five from the third. The midrib of the third leaf is marked p in Diagram I. 
At the second node seven traces from the first leaf enter the axis, and form 
an outer circle (Diagram III, Text-fig. 17). 
P P 
P 
n 
t 
IV. 
Text-fig. 17. Avenct sativa, L. Diagrams from much older seedling, showing base of plumule. 
I. Second internode. Axis sheathed by base of first leaf as well as coleoptile. II. Approaching 
second node. Ax 2 is bud in axil of first leaf. III. Base of first internode. Axis sheathed by 
coleoptile only. Ax x , bud in axil of coleoptile. IV. First node. Rp. y Rp'., root-plates. 
The first internode is undeveloped : there is no interval between the 
second and the first node. The upper limits of the two nodes are, however, 
marked by the insertion of two lateral buds, Ax 2 in the axil of the first leaf 
(Diagram II), and Ax 1 in that of the coleoptile (Diagram III). Both 
buds are embryonic, and do not yet receive any vascular elements from 
the stele. 
