THE ABORTIVE SPIKE OF BOTRYCHIUM 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 1 64 



O. O. Stoland 



(WITH TWENTY-ONE FIGURES) 



Interest in the study of the vascular anatomy of the Ophioglos- 

 saceae has increased since Chrysler's work 1 on the nature of the 

 fertile spike appeared in 1910. He made the vascular supply of 

 the leaf the basis for concluding that the fertile spike represents two 

 fused basal pinnae. The nature of the vascular supply of the 

 abortive spike has so far received no special 

 attention. 



This investigation was undertaken to deter- 

 mine the origin and nature of the vascular 

 supply of the abortive spike, and to compare it 

 with that of the sterile pinnae and the fertile 

 spike. Chrysler found that the series of 

 changes undergone in the origin of the strands 



same 



J 



2 



those for the fertile spike. 



The material studied was Botrychium virgini- 

 anum, the species from which Chrysler made 

 his figures illustrating the origin of the strands 

 to the fertile spike and sterile pinnae, 

 abortive spike is of very common occurren 

 this species. It appears on the adaxial side of first pair of pinnae 



cut off; one-half 

 natural size; fig. 2, 

 lateral view of same. 



The 



Figs, i, 2.— Fig. 1, 



adaxial view of the 

 petiole, with the 

 abortive spike and 



minute structure about 2 cm 



below the first pair of sterile pinnae (figs. 



1 



2). 



The fertile spike, however, always comes off 

 from the main axis slightly below the first pair of pinnae. The 

 elongation of the petiole after the abortive spike separates from 

 the axis leaves it some distance below the first pair of pinnae. 



1 Chrysler, M. A., The nature of the fertile spike in Ophioglossaceae. Ann. 

 Botany 24:1-18. figs. 1-16. ph. 1, 2. 1910. 



525] [Botanical Gazette, vol. 54 



