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these are characterized by growing in small, compact tufts, 

 resembling moss-tufls in form. The plants stand very close 

 together and in considerable numbers in these colonies. The 

 formation of these can only be explained by the fact, that the 

 fruit-stalk has fallen down before the capsule had opened and 

 that the seeds have germinated in a heap. So no real dispersal 

 of the seeds has taken [)Iace in these two cases. Whether 

 the colonies of seedlings mentioned here are common in 

 temperate regions I myself have not been able to investigate, 

 and in the literature of the subject 1 have never met with any 

 notes regarding this fact. 



Ecological studies on arctic plants should be based on 

 species widely distributed both in cold and temperate regions, 

 and then only can there be a possibility of an interesting 

 comparison, and in this respect the genus Pinguicida is 

 well qualified. It contains three species, inhabiting arctic and 

 temperate countries, the one, P. vulgaris^ thrives well both in 

 the level lands of Central Europe and on rocky walls in arctic 

 regions, another, an alpine species, and finally a purely arctic 

 one, F.villosa. The most variable of these three, P. vulgaris, 

 requires, however, everywhere in its wide geographical area, the 

 same conditions, mainly with regard to water. The possibility 

 of the arctic specimens being very differently formed in their 

 anatomical characters from the temperate ones, must already in 

 consequence of this be regarded as very small. On the other 

 hand, the rather complicated shoot-structure of this species could 

 better be thought to be subject to a reduction, produced by the 

 conditions in arctic regions. Here, the late commencement of 

 the summer will delay the development of the spring-rosette 

 and, at the same time, of the flower (Hartz, Rosenvinge, Jonsson). 

 The flowering, which takes place in Denmark usually in May — 

 June, will for instance in Greenland not occur before June or 

 July; in August — September the winter-bud must be developed 

 because the night-frost comes already at this time. A reduc- 



