THE FERN BULLETIN 



75 



not tend to hasten growth and maturation, such as may- 

 be expected in the sandy and rock soils in which the 

 majority of the collections were made. The case at 

 Bagotville may be accounted for by its location far 

 north, about 48°. It is well known that the same spe- 

 cies mature fruit later in northern than in southern 

 home. Plants whose times of fruiting differ by sev- 

 eral days or even weeks in their stations farthest south 

 have this difference in time gradually lessened as they 

 range northward till they reach a parallel where their 

 maturation coincides. I was especially struck by this 

 in the case of two of our common blueberries, both in 

 great abundance in this part of Canada, where they 

 are gathered in large quantities for canning. In the 

 latitude of Chicago the early blueberry (Vaccinium 

 P ennsylanicum ) begins to ripen about the 20th of June; 

 the Canada blueberry (V. Canadense) two or three 

 weeks later, though not much later in anthesis. But 

 the berry-pickers by the Saguenay river harvest them 

 simultaneously, as both ripen in August and continue 

 in good condition till the frosts in early September 

 destroy them. As the two species grow intermixed 

 there is no difference in soil conditions. Climate alone 

 seems to account for this identity in time. The short- 

 ened summer forces this parallel development of plants 

 whose seasons differ in lower latitudes. Nor are the 

 ferns an exception to the rule. 



It would appear from this that B. obliquum is later 

 in fruiting than B. tern a turn intermedium, or that the 

 latter takes more nataially to a habitat which insures 

 an earlier development. This difference in time may 

 amount to two or three weeks or more, and if con- 

 firmed by further experience and more extended appli- 

 cation will prove of diagnostic value in the separation 



