igi2] STOLAND— SPIKE OF BOTRYCHIUM 531 



where the vascular supply of the fertile spike is derived from curved 

 rows of strands. 



Summary and conclusions 



1. The leaf trace of the petiole bearing the abortive spike con- 

 sists of several bundles instead of two bundles as usually found in 

 the petiole bearing the fertile spike. 



2. The vascular supply of the abortive spike consists of two or 



four strands arising from the edges or the base of the gap in the 

 leaf trace. 



3. The pair of sterile pinnae following the abortive spike are 



same 



those for the abortive spike, 



4. Xylem may or may not appear in the strands to the abortive 

 spike, but it never appears throughout the entire strand. 



5. The difference between the origin of the strands to the 

 abortive spike from those to the fertile spike is very slight. 



6. The nature of the vascular supply of the abortive spike 



supports Chrysler's contention that it represents two fused basal 

 pinnae. 



This work was undertaken at the suggestion of Professor 

 Coulter and under the direction of Dr. Chamberlain, and I wish 

 to express my appreciation for their valuable suggestions and criti- 

 cisms. I also wish to express my thanks to Dr. M. A. Chrysler 

 for valuable criticism. 



UVIVERSITY OF CHICAGO 





