GROUPING AND MUTATION IN BOTRYCHIUM 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 273 



Charles J. Chamberlain 



(with eleven figures) 



Ever since the appearance of Chrysler's 1 paper, claiming that 

 the fertile spike of Botrychium represents a pair of fused pinnae 

 of the vegetative leaf, I have been interested to note the peculi- 

 arities in the spore-bearing portions, upon which he relies for a 

 part of his evidence. Two fertile spikes in the position of the lower 

 pair of leaflets, spikes in which the two component leaflets are 

 incompletely fused, sporangia on the second pair of leaflets in 

 addition to the sporangia of the fertile spike, and occasional 

 sporangia on vegetative leaves were found during vacation field 

 studies of Botrychium obliquum and its varieties. Chrysler's 

 claim needs no support, his evidence both from field study and 

 anatomy being so convincing that, for years, we have treated these 

 forms as a mere family, Ophioglossaceae, under the Filicales. 



However, the field studies, carried on for several years during 

 September vacations in Ohio, at Oberlin, Sullivan, Cleveland, and 

 Birmingham, together with a few observations at Osborn, Indiana, 

 and at Fort Sheridan, Illinois, impressed upon me that one scarcely 

 ever finds isolated plants of Botrychium. They are almost invari- 

 ably grouped; even when there seems to be an isolated plant, 

 others can usually be found in the immediate vicinity. 



In Ophioglossum there is abundant vegetative propagation by 

 branching of the rhizome, so that not only are the plants grouped. 

 but the plants of a group are more or less connected. In strik- 

 ing contrast, Botrychium shows no vegetative propagation. The 

 rhizome scarcely ever branches and, when it does, the branch is not 

 likely to become separated and form a new plant. Every plant 

 comes from a pro thallium. Consequently the distribution is 



The 



Ann. 



/ — # 



Botany 24: 1-18. 1910 

 387] 



[Botanical Gazette, vol. 70 



