1911] TUPPER—GINKGO BILOBA Sit 
as appendages of the rays. The crystal-containing cells seem to be 
a modification of the parenchyma cells. 
The fact that all of the xylem parenchyma found in Ginkgo is 
very differently distributed from that found in the conifers (radial 
and not tangential) suggests that it is a primitive type. 
The short shoots of Ginkgo frequently divide within the wood 
of the branch. The only one of the conifers which is known to 
have such a peculiarity is the new araucarian genus Woodworthia. 
This work has been done in the Phanerogamic Laboratories 
of Harvard University. The writer is indebted to Professor 
JEFFREY for advice and guidance throughout the investigation, 
and for aid in securing the accompanying photomicrographs. 
Harvarp UNIVERSITY 
EXPLANATION OF PLATE XX 
Ginkgo biloba 
Fic. 1.—Radial section of root, showing crystal-containing cells in contact 
With a ray, and distributed in a row (intermingled with parenchyma cells) 
which runs longitudinally along the root; parenchyma growing out from rays; 
X 8o. 
Fic. 2.—Radial section of root, showing two rays connected by a row of 
crystal cells; 80 
1G. 3.—Tangential section of root; X8o. 
Fic. : —Transverse section of root; 8o. 
1G. 5.—Transverse section of branching short shoot, showing the divisions 
entirely Sa from each other, yet still within the wood of the branch; 
X12 
Pin: 6.—Transverse section of branching short shoot seen in fig. 5, sectioned 
nearer in toward the pith of the branch, showing the short shoot undivided; 
X12. - 
