112 ^ 



By way of summary it may be stated that the distributional 

 phenomena herein described represent the cumulative effect of 

 dynamic physical and chemical forces, some of which have long 

 since become inactive while others continue to exert a modifying 

 influence upon the physiognomy of plant life. In so* far as they 

 have either hindered or facilitated plant dissemination historical 

 factors in a general way may be regarded as directly responsible 

 for the composition of the local flora, while indirectly those 

 glacial and preglacial forces which moulded the present physio- 

 graphic features of the landscape still affect the character of the 

 vegetation. To a very appreciable degree certain observed 

 aspects of plant distribution are associated with contemporaneous 

 conditions of topography, soil, and climate. 

 Yale University. 



SHORTER NOTES 



BOTRYCHIUM OBLIQUUM AND VAR. DISSECTUM IN BeRRIEN Co., 



Michigan. — The seventh edition of Gray's Manual records these 

 two plants as often occurring together in New England, New 

 York, and Ohio. It may be of interest to note that they occur 

 further westward, and possibly throughout the entire range of 

 the typical form. October 19, 1912, in company with a class 

 from the University of Chicago, I found several specimens of 

 both growing together in an open wood near Sawyer. E. J. 

 Hill in the Fern Bulletin for April 1912, states that both are 

 found in Peoria Co., 111., although he does not say that they are 

 found together. 



It is also of interest that while all the plants of the species 

 were large and fertile (the spores not yet shed), those of the 

 variety were only about one third as large, and consisted of the 

 sterile segment only. It would appear from the specimens 

 examined that dissectiim is only a juvenile form of the species, 

 but the material is too scanty to draw any conclusions as to this. 



Edwin D. Hull 



