6 research outputs found
Historical Background of the Flora of the Pacific Northwest
66 pagesThe modern flora of the Pacific Northwest is characterized by associations which show affinities to floras
now occupying widely separated areas (Eurasia, South and Central America) and to floras shown by paleobotanical
evidence to have occupied all these areas, but particularly the American West. Distinct distribution
patterns, both in time and space, manifest themselves. These patterns are and have been influenced by
topographic and climatic changes from the Cretaceous to the present. Three principal sources of associations
are evident: evolution in situ; northern regions as shown in the Arcto-Tertiary Geoflora; western Mexico
and the southwestern United States as shown in the Madro-Tertiary Geoflora.Funds for publication of Bulletin No. 13
provided by the National Science Foundation,
grant GB 3670
CONCENTRATION OF ENVIRONMENTAL EXTREMES AS THE BASIS FOR VEGETATION AREAS
Volume: 9Start Page: 169End Page: 18