530 Sinnott and Bailey. — The Significance of the ‘ Foliar Ray ’ 
as of so much importance, is really but a temporary phase in the evolution of 
the herbaceous stem, since it is stated to be absent in the woody prototypes, 
to be present in transitional herbs, and to disappear again as the herbaceous 
structure reaches its fullest development. 
The essential difference between our position and that of Jeffrey and 
Torrey as to the evolution of the herbaceous stem may be concisely shown 
by the following series of diagrams. Our critics derive the herbaceous type 
from such a woody stem as is represented in A, where wide rays, flanking 
A. Transverse section of one-year-old stem of arborescent or fruticose Dicotyledon, which is 
devoid of wide, high multiseriate rays. B. Transverse section of one-year-old stem of arborescent 
or fruticose Dicotyledon whose woody cylinder is dissected into separate strands by wide, high 
multiseriate rays. C. Transverse section of stem of woody or ‘ transitional ’ herb showing ‘ con- 
fronting’ and ‘flanking’ parenchyma — the condition .which is emphasized by Jeffrey and Torrey 
in their theory of the origin of the herbaceous type. d. Transverse section of slender, herbaceous 
stem which is devoid of ‘foliar storage rays’, e. Transverse section of slender, herbaceous stem 
whose stele is dissected into a series of discrete woody strands. 
the leaf-traces, are absent. From this ancestor arises the transitional herb, 
C, possessing ‘foliar rays’, a stage particularly emphasized by Jeffrey and 
Torrey. From this, in turn, through the disappearance of the confronting 
portion of the foliar ray is derived the typical, many-bundled herbaceous 
stem of advanced type, E. In this sequence conditions at the node are 
particularly emphasized. 
According to the view of the writers, based on a study of the whole 
aerial stem, the condition in E may be derived directly from such a woody 
ancestor as shown in B. In the latter type well-marked flanking rays are 
