Re: low latitude paleoflora

["Tyrberg Tommy" <tommy.tyrberg@aerotechtelub.se>]

> The current knowledge of the unquestionable 
> presence of Osmundaceae, Cyatheaceae, Lophosoriaceae, Marattiaceae and the 
> possible presence of Schizaeaceae, Lygodiaceae and Polypodiaceae allow us to 
> recognize ferns as a diverse group in the Early Cretaceous plant communities 
> of the South Shetlands Islands. According to the present requirements of 
> those families, some of which are restricted to montane forests, tropical 
> and subtropical, the climate was mild enough YEAR around, so that these 
> ferns could reach an important ecological role in the community, which is 
> reflected in the fossil record. 

Just to put the biogeographic record right, the following families of conifers 
and "ferns" (speaking very loosely) occur well north of the arctic circle in 
Scandinavia even in the present "icehouse" climatic regime:
Equisetaceae
Isoetaceae
Lycopodiaceae
Ophioglossaceae
Polypodiaceae
Selaginellaceae
Cupressiaceae
Pinaceae

These eight should thus qualify as at least subarctic, while the following 
three reach about 60 degrees north in the same area and are therefore decidedly 
cold-temperate:

Osmundaceae
Marsileaceae
Taxaceae

Anybody know if any additional families reach that far north in Siberia or 
Alaska/Canada?

Tommy Tyrberg