1912] HOLDEN—SAPINDALES 57 
Summary and conclusions 
1. Investigations of the anatomy of living and fossil gymno- 
sperms have proved certain general principles. One is that 
primitive structures occur in the fibrovascular bundles of the leaf 
petiole, the root, and the reproductive axis, and sometimes revert in 
wounded wood. 
2. Of the Sapindales investigated, three show multiseriate rays 
normally: Acer, Sapindus, and Staphylea; the fourth, Aesculus, 
shows uniseriate rays normally, but multiseriate rays in the leaf 
petiole, root, and reproductive axis. 
3. Applying the general principles enumerated above, it is 
evident that the multiseriate type of ray is primitive for the Sapin- 
dales, and that Aesculus is a degenerate member. Accordingly, the 
Sapindales belong high in any systematic arrangement of dicoty- 
ledonous woods. 
In conclusion, I wish to express to Dr. E. C. JEFFREY my sincere 
thanks for his suggestions and advice during the course of this 
investigation. 
RADCLIFFE COLLEGE 
CAMBRIDGE, Mass. 
EXPLANATION OF PLATES II AND II 
PLATE II 
Fic. 1.—Aesculus Hippocastanum; transverse section of wood, showing 
uniseriate rays; X 8o. 
Fic: 2.—The same: tangential section of wood, showing similar rays; 
X 80. 
Fic. 3.—Acer saccharum: tangential section of wood, showing multiseriate 
rays; X8o. 
Fic. 4.—Sapindus sp.: transverse section of wood, showing multiseriate 
rays; X8o. 
Fic. 5—The same: tangential section of wood, showing similar rays; 
X80. 
Fic. 6. oe trifolia: tangential section of wood, showing multi- 
seriate rays; X80 
PLATE III 
Fic. 7.—Aesculus Hippocastanum: transverse section of leaf petiole, 
showing multiseriate rays; 1 
