I9I5 ] PETRY—OPHIOGLOSSACEAE 363 



Summary 



1. Branching of the rhizome of Ophioglossum vulgatum and 0. 

 pendulum is dichotomous ; there are no axillary or adventitious 

 buds on the rhizome. 



2. Axillary buds are regularly present in five species of Botrych- 

 ium. 



3. The vascular connections of the branches in Botrychium vary 

 widely with the species and with the individual specimen. It is 

 concluded that the details of the vascular supply of the branch are 

 controlled by the conditions of development and are therefore of 

 little or no phylogenetic importance. 



4. In wounded rhizomes of B. obliquum, renewed activity of the 

 cambium produces considerable masses of accessory xylem; the 

 pith frequently develops sieve tubes and a cambium which produces 

 secondary xylem in quantity; the pericycle often produces sieve 

 tubes and secondary xylem. It is concluded that in this species 

 any stelar tissues capable of growth may produce vascular elements 

 under the influence of an injury. 



5. The axillary bud of B. obliquum arises as a plate of meriste- 

 matic cells on the adaxial face of the base of the very young leaf; 

 it develops without differentiation into a plate of meristematic 

 tissue one or two cells in thickness and 50-60 cells in area, which is 

 buried by overgrowth of surrounding tissue. 



6. The data secured is in agreement with the evidence pointing 

 to a relationship of the Ophioglossaceae to the primitive ferns, 

 especially the Zygopterideae. 



Syracuse University 

 Syracuse N.Y. 



The writer wishes to acknowledge the kindness of Professor 

 John M. Coulter in placing the facilities of the Hull Botanical 

 Laboratory at his disposal; and to express his thanks to Dr. W. J.G. 

 Land for material of Trichomanes. 



