456 



(^onceriiiiiji llic lirsl ol' lliesc points, however. I cannot tor 

 the present comnuinicate any results, in the liitnre I liope lo 

 be able lo do so. .1 priori we n)ay venture to I hink tliat J\ vil- 

 /osa. il' cultivated in Denmark, will continuously retain its arclic 

 type, bein^' undoubtedly, of the three species in question, the 

 oldest inhabitant of arctic countries, and in herbarium material 

 I never, even far down in Sweden, perceived 

 any trace of development of an aulumn- 

 roselle. With respect to P. alpina there is 

 nothing interesting to state on this point, 

 but as regards P. vulgaris, the result of 

 its cultivation is subject to greater doubt, 

 and in consequence of this, such experi- 

 ments with this species have a greater 

 value. Whether the arctic type here is 

 constant, it is quite impossible to say, 

 though probability tends to the contrary. 

 Concerning the determination of a 

 geographical limit. I have been more 

 successful. P. vulgaris being a circum- 

 polar species, one would with such a 

 phyto-geographical line (a sort of Biocho- 

 rus) be able to state the influence of the 

 arctic climate upon a particular plant, 

 and such a result would not be without 

 interest. A line of this sort must na- 

 turally be exceedingly difflcult to draw; in order to be able to 

 arrive at a satisfactory result a great many observations in 

 nature are required, made mainly in July or August. Only when 

 this has been done in regard to the main points, will it be 

 possible to proceed to the determination of the climatic factors 

 distinguishing the two types. 



If we take the opposite view and draw the geographical 

 limit on the basis of the already existing climatological material. 



y 



Fig. 4. 

 Pinguicula alpina. 



Auluinn-rosRtte is deve- 

 loped; the fruit-stalk i* 

 pushed somewhat to one 

 side by the rosette. Pla- 

 teau de Murnau (Haute 

 Bavière). June. About Vï 

 natural size. (H.E.P. phot.) 



