1048 
de Fraine . — On the Structure and 
in 5. insignis. The phloem round the radially symmetrical bundles is 
unfortunately always absent, though its preservation is almost perfect in 
some of the unilateral strands. When present, the bast forms a complete 
zone around the wood, though the distribution may be somewhat unequal, 
the thickness being greater on the side remote from the fibrous strands 
j 
1 
i / 
\ 
1 
! 
Text-fig. 14. Transverse section of a radially symmetrical leaf-trace bundle, just passing out 
through the secondary wood xy 2 . x 55. The arrow indicates the direction in which the bundle is 
moving, p.xy. = protoxylem ; xy 1 . = primary xylem ; par . = wood parenchyma ; ty. = tyloses. 
(Compare with Scott’s S. insignis , PL IX, Fig. 14.) 
(Text-fig. 3). A very characteristic feature of the phloem of the leaf-trace 
strands is the presence of a ring of large elements, usually occurring in the 
outer zone of the bast, though it may in places abut on the wood (Text- 
fig. 3)- These large cells may occur singly, or two or three together, in the 
