DISJUNCTION AND ENDEMISM IN THE FLORA OF THE CENTRAL WESTERN CASCADES OF OREGON: AN HISTORICAL AND ECOLOGICAL APPROACH TO PLANT DISTRIBUTIONS
Datum
1968-12
Autor:innen
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Verlag
University of Oregon
Zusammenfassung
The Western Cascades of central Oregon comprise a unique area
of great floristic diversity. Included in the flora of the area are
numerous species with disjunct distributions. About 95 percent of this
region supports some phase of the broadly-defined mesic conifer forest
(Detling, 1968), a low diversity floristic unit dominated by Pseudotsuga
menziesii and species of Abies and Tsuga. Occurring in clearings,
meadows, bogs, and on scree slopes and outcrops are numerous additional
species many of which are typical of this region of the Cascades. However,
approximately 20 percent of the flora of the region consists of
species characteristic of other regions. These species are disjunct,
often markedly so, in their Western Cascade occurrences. They are concentrated
in, but not restricted to, the non-forest habitats. Disjunct
elements in the Western Cascade flora include boreal, high alpine,
Siskiyou-Klamath, Great Basin, and lowland valley species. Three species
are endemic to the study region and its immediate environs. The
study of the distributions of these disjunct and endemic species is the
subject of this work.
Beschreibung
346 pages