62 MORPHOLOGY OF SPERM ATOPHYTES 



invested by a very distinct bundle sheath, in which two vascular 

 bundles of the ordinary collateral type are developed. The re- 



FIG. 46. Branch from Podocarpus Purdieana. From photograph of herbarium speci- 

 men, two thirds natural size. 



maining tissue within the sheath is organized as " transfusion 

 tissue," consisting of two kinds of parenchymatous cells, (1) 

 those without protoplasm and pitted, and (2) those with proto- 



