Anatomico-physiological Relations in the Spermophyte Shoot . 153 
of those properly belonging to node 4 were placed so near together that a 
deeper fusion of tissue than usually takes place may be supposed to have 
existed, with the result that the line of contact between them no longer pos- 
sessed the character of a ‘potential ’ edge and hence produced neither hairs 
nor contour ridge. In the upper region of the stem, as already described 
(p. 143), the leaf- divergence is f and the leaf-insertion width perhaps 
a trifle more than of the circumference. The contour lines diverge 
Figs. 26-29. 2 6, Lopezia coronata , stem in transverse section showing the contour lines of the 
leaf-extensions as eight ridges flanked with a line of hairs. 27, Calystegia dahurica , showing similar 
ridges without hairs. 28-29, Antirrhinum Orontium , hypocotyl in transverse section showing an 
early and a later stage in the development of an exogenous adventitious bud. 
slightly from a straight course, so that of the two terminating at each node 
one ends in mid-axil, the other to the side and close to one of the minute 
stipules. The ‘ lie 5 of the pattern is therefore not truly in line with the axis, 
but slightly askew. Owing to this cause and to some slight departure from 
a parallel course, the two contour lines from each leaf-insertion now run 
through three and five internodes respectively (see Figs. 12 and 23) instead 
of only through two and three internodes, as is the case with the same 
arrangement when the fusion lines run parallel to the axis (as shown in 
Fig. 11). As the hair lines flank each ridge and as contiguous hair lines 
N 2 
