PALYNOLOGY AND PLEISTOCENE ECOLOGY 371 



In Speaking of the border-lines between palynology, cytology, and cyto- 

 taxonomy, a few words may be added concerning pollen grains in some species 

 of Sanguisorba (cf. Erdtman and Nordborg, 1961). Here, from size and other 

 morphological details, it seems possible to determine the chromosome race 

 (2n = 28 or 56, etc.) to which the pollen grains belong. This is true both with 

 regard to fresh grains and, in certain cases at least, with regard to fossil, 

 e.g. Late Glacial, pollen grains. The example favors a view expressed by 

 Stebbins (1959): "In view of the fact that the characteristics of pollen which 

 distinguish modern species are becoming much better known while discoveries 

 and analyses of fossil pollen are also greatly increasing in number, the com- 

 bination of these two types of data for the purpose of tracing out the ancestry 

 of polyploid complexes would seem to be a valuable new avenue of approach 

 which deserves attention." 



Apocrats and the history of the Icelandic biota. To me, mention of the 

 nature of Iceland conjures up the vivid description in the book "Till Hackle- 

 fjall" by the Swedish author and artist Albert Engstrom. Therefore I must 

 restrain myself and point out only one or two things that may possibly be of 

 interest to future palynological investigators concerned with ecological and 

 phytogeographical conditions in Iceland. 



The mixture of ice and fire, of volcanism and glaciation, contribute to 

 make Iceland a rewarding place for the study of apocratic biota, "obligate" 

 as well as "facultative". Furthermore, Iceland is only sparsely inhabited and 

 one may thus expect a more distinct difference — or at least one more easily 

 disentangled — between apocrats and statocrats than in densely populated, 

 heavily trafficked areas. 



"Tephrochronology" is a term introduced by Thorarinsson (1944). Not 

 only volcanic ash (Greek tefra = ash) as indicated by this term, but also 

 other products of volcanic activity have interfered with the natural vegetation. 

 Which are, or were, the main phases of regeneration? Which apocrats 

 correspond, ecologically, to, for example, the scattered, very characteristic 

 Eriogonum spp. around Crater Lake, Oregon, or to the "pioneers" on the slopes 

 of Mt. Etna and Mt. Vesuvius? 



And, with regard to the immigration of plants on virgin soil laid bare at the 

 retreat of glaciers, which plants in Iceland correspond to those invading 

 similar soils in other parts of the world, in Alaska, at the end of the Rhone 

 Glacier in Switzerland (cf. Flora 146, p. 386, 1958), etc.? 



The interrelationship between certain apocratic elements along the sea coast 

 and common "weeds" as well as certain "continental" elements on high 

 mountains, inland plateaus, etc., far from the coasts or other places where 

 their nearest relatives occur, ought to be studied (cf. also Godwin, 1960). 

 Ten to twenty years ago some of the leading taxonomists and phytogeo- 

 graphers apparently paid only scant attention to some of the apocratic news 

 of that time (e.g. the occurrence of pollen grains of Artemisia, Centaurea 



