5 o9 
of Schizaeci malaccana . 
protoxylem corresponds in position with the spiral elements 
of the leaf-bundle. At the point where a leaf-trace is leaving 
the stele the tracheids are first formed in the stele above the 
point of departure of the trace at a higher level than in the 
trace itself. The tracheids likewise increase in number till 
they form a fairly complete ring, normally one or two cells 
thick. 
The endodermal and pericyclic cells occasionally divide by 
additional walls, either radial or tangential. The increase in 
the number of cells on the circumference of the stele is, how- 
ever, comparatively small from the period of the separation 
of endodermis and pericycle initials right up to the period 
when differentiation of all the tissues is complete. 
EXPLANATION OF PLATES XXV AND XXVI. 
Illustrating the paper by Mr. Tansley and Miss Chide on Schizaea malaccana. 
Fig. i. Plant of Schizaea malaccana , half natural size. 
Fig. 2. Pinnae of a fertile frond seen from below, x 4. 
Fig. 3. Transverse section of stele of stem of rather small plant (stem *8 mm., 
stele *2 mm. in diameter) showing departure of a leaf-trace, two endodermal cells, 
end. r., continuous above with inner part of endodermis of leaf-trace ; and endo- 
dermal pouch, end. p ., enclosing four cells of same histological character as 
cortex and continuous with cortex at departure of next leaf-trace above, x 232. 
Fig. 4. Transverse section of stele of larger stem (stem 1 mm., stele -3 mm. in 
diameter) showing departure of leaf-trace ; one-sided endodermal pouch, end. /., 
belonging to it, and enclosing two cells of same histological character as cortex ; 
endodermal rod, end. r. } consisting of seven cells, belonging to next leaf-trace above ; 
and internal tracheids, ini. lr., part of a strand continuous with edge of leaf- 
gap above and ending blindly below, x 270. 
Fig. 5. Transverse section of stele of large stem (stem 1-5 mm., stele *54 mm. 
in diameter) showing unusually rapid departure of leaf-trace and closure of gap 
in xylem-ring. Int. tr., internal tracheids forming almost complete band across 
the pith, x 100. 
Fig. 6. Part of transverse section of leaf passing through the two stomatic rows 
on the lower surface ; on the left a large inter-stomatal cell (i. si. c.) ; on the 
right a stoma (si.). In the meristele the two lateral groups of fibres (s. t.f.) lie 
between the sieve-tubes (s. t.) and the lateral tracheids (tr.). Px., obliterated pro- 
toxylem. x 150. 
Fig. 7. Longitudinal section passing through side of meristele of leaf. Letters 
as in Fig. 6. x 200. 
