326 T. G. Hill and E. de Eraine. 
sides of the vascular strands: although commonly they extend 
outwards as far as the lateral limits of the phloem, they may extend 
on the dorsal and ventral sides 
In one seedling transfusion 
tracheides were found in the 
mesophyll well towards the 
periphery of the cotyledons and 
forming an interrupted zone of 
groups of cells extending about 
half-way round the circumfer¬ 
ence of the seed-leaf. These 
cells always retained their iso¬ 
lated position : in no case were 
they seen to become connected 
by similar elements with the 
vascular bundle. It is thus seen 
that the transfusion-tracheids 
in Persoonia corresponds to 
what obtains in many Gym. 
nosperms. 1 
Incidentally it may be men¬ 
tioned that the transfusion 
tracheides of Persoonia are not 
restricted to the cotyledons: 
they may occur in the upper 
region of the hypocotyl and 
in the foliage leaves of Persoonia lanceolata and P. juniperina. 
The elements in question arise in no very definite order, as is 
shewn by the irregular appearance of immature tracheides amongst 
mature dead ones. Thus, in Figure 6, whilst those at the apex are 
mature, some lower down, shewing rather indefinite thickenings and 
containing protoplasm and nuclei, are immature. Again in Figure 
9, immature elements occur with adult ones on the flanks of the 
bundle. 
The size of the transfusion tracheides varies : at the apex of 
the seed-leaf (Figures 6, 7 and 8) their dimensions, as viewed in 
See Bernard : Le bois centripete dans les feuilles de Coniferes. 
Beih. Bot. Centrbl., 1904, XVII. 
Daguillon : Recherches morphologiques sur les feuilles des 
Coniferes. Rev. Gen. Bot., 1890, II. 
Hill and de Fraine : Seedling Structure of Gymnosperms, I, II, 
and IV. Ann. Bot., 1908, XXII ; 1909, XXIII ; 1910, XXIV. 
further (Fig. 5) and also may occur 
of the bundle (Figs. 9, 10 and 11). 
Fig. 8. P. lanceolata. Transverse 
section near tip of cotyledon. Trans¬ 
fusion tracheides are seen extending 
towards the periphery, x 335. 
