498 
Gwynne- Vaughan. — On some Climbing.. 
xylem is formed (Text-fig. i, C 3 ), and the. inner protoxylem again divides 
(Text-fig. J , C 4 ), giving rise to the proximal lateral protoxylem of the 
branch, and the protoxylem remaining in the parent axis (Text-fig. i, c 4 , c 5 ). 
The median protoxylem of the petiolar bundle takes Ho part in the branch-' 
ing ; if there is a true median protoxylem of the primary branch-trace 
it must arise de noVo. In other respects the structure of the trade of the 
primary branch resembles that of the petiolar trace* 
The primary branch bears two secondary branches opposite one 
another and then ends blindly (Text-fig. ] A). 
The origin and structure of the trace to a secondary branch are 
Text-fig. 2. Lygodizim japonicum . A. Habit sketch, fi. Diagrammatic transverse section 
of xylem strand of petiolar trace at base of petiole. C. Diagrammatic transverse section of petiolar trace 
in free petiole. D 1-6 . Departure of xylem strand to primary branch of the petiole. E 1-3 . Same, to 
secondary branches. F. Same, to tertiary branch. 
similar to those of the trace to a primary branch, but the abaxial prominence 
is less marked. The outline is oval ; protophloem and small sieve-tubes 
surround the xylem. Only one group of large sieve-tubes is present, and 
lies on the abaxial side ; on the adaxial side and also near the lateral ends 
incipient fibres occur. The median prominence of the xylem is more 
or less obsolete, and the only protoxylems present are the two adaxial 
lateral groups (Text-fig. 1, D). 
