JOURNAL OF MICROSCOPICAL SCIENCE. 



PLATE V, 



Illustrating Professor Thiselton Dyer's paper on tlie Structure 

 of the Stem of the Screw Pine. 



Fig. 

 1. — Transverse section of a portion of stem of Pandanus utilis, Bory, 

 X 14. The small chequered areas in the upper part of the figure 

 represent sections of the external evascular bundles. The larger 

 areas in, the lower part are the central fibro-vascular bundles. The 

 dark cells bordering each contain the crystals. The clear round 

 spaces in upper part are enlarged parenchymatous cells originally 

 containing raphides. 



2. — Transverse section of one of the evascular fibrous bundles X 450. 

 The prismatic crystals are seen 'hi situ, in the marginal cells. The 

 cell-walls of the surrounding parenchyma are porous. 



3. — Longitudinal section tangential to a fibro-vascular bundle X 450. The 

 strings of crystal-bearing cells are seen to lie externally to 

 the elongated liber cells. The large cells on the left belong to the 

 general parenchyma. 



4. — Longitudinal section (somewhat diagrammatic) of the internal portion 

 of a fibro-vascular bundle X 450. It represents in ascending order 

 from below upwards the following parts -.—first, porous cells of the 

 general parenchyma compressed laterally ; secondly, a spiral vessel ; 

 thirdly, wood-cells ; fourthly, scalariform vessel with three of its sides 

 in view ; ^^^ finally, a liber-cell. 



