546 Rivett . — The Anatomy of Rhododendron ponticnm , Z., and of 
Diagram XV. Internodes numbered from base to apex. (Scale, 5 internodes — 1 cm.) 
Diagram XVI. Internodes numbered from base to apex. (Scale, 5 internodes — 
cm.) 
tliat there are one or more large groups of very numerous small vessels 
occupying certain sectors. These are the conducting elements which 
connect with the strands of the petiole and the axillary bud : they exert 
