TAXONOMIC DIFFERENTIATION 



91 



with Diyas octopetala, also recently studied by Hulten (1959b). But nobody 

 can predict the results of detailed and careful cyto-taxonomic studies. 







Fig. 2. The Scandinavian distribution of Poa jemtlandica (Almqu.) Richt. (After 



Nannfeldt, 1937.) 



1 turn now to the problem whether the taxonomic differentiation between 

 populations in different parts of the Scandes can give clues to an under- 

 standing of their migratory history. The now classical example is the mountain 

 poppies, studied by Nordhagen (e.g. 1931) from the late twenties onwards and 

 then given a detailed cyto-taxonomical treatment by Gunvor Knaben (1958, 

 1959 a and b). Love (1955, 1962) has studied these poppies in other part-areas. 



