A biosystematic investigation was undertaken in 15
species and three subspecies of the genus Aster, in western
North America. Previous studies had been based entirely on
external morphological features, and it was believed that
much could be learned about the natural affinities of the
taxa by exploring their cytological and...
Arctostaphylos viscida Parry and A. canescens Eastw.,
two well-known and frequently encountered manzanitas in the
Siskiyou Mountains in southwestern Oregon, are shown to
hybridize and to produce an extensive series of morphological
intermediates. The hybridization occurs wherever populations
of these two species meet at contact zones of
serpentine and non-serpentine...
A taxonomic investigation was made of 24 taxa belonging
to the section Trichodium (Michx.) Trin., of
Agrostis, and the genus Podagrostis. Experimental methods
were employed, including: uniform garden culture of transplants
and plants grown from seeds collected in natural
populations; breeding studies; physiological and phenological
investigations; cytological studies; ecological
studies...
A cytogeographic study, the relationship between chromosome
number and geographical and ecological distribution, was made of the
tetraploid and hexaploid chromosome forms of Achillea millefolium L.
in western Oregon. Principal objectives of the investigation were
three. First was a determination of the exact distributions of the two
levels, as previous...
The Artemisia ludoviciana polyploid complex is a highly polymorphic
assembledge of eight taxa in the Pacific Northwest, with a
chromosome base number of x=9. A cytogenetic analysis of this
complex was carried out to determine the sources of its variation,
the types of polyploidy present, and the genetic processes active...
A gene-ecological transplant study was made on populations of
the Crepis nana and C. elegans complex from the Arctic and Alpine of
North America. Transplants were collected from the Brooks Range,
Eagle Summit, and Alaska Range in Alaska, the Rocky Mountains in
Alberta, the Olympic Mountains in Washington, the Wallowa...
A cytogeographical study was made of populations of tetraploid
(n=18) and hexaploid (n=27) Achillea millefolium (Compositae-
Anthemideae) from the Pacific Coast states. There is a complex
distributional pattern, involving overlapping ranges, mixed populations,
migration of one form into areas occuplied by the other,
pentaploid hybrids, and septaploid and octoploid plants....
A biosystematic study was made in seven populations of Mimulus
nanus Hook. & Arn. and M. cusickii (Greene) Piper (Scrophulariaceae)
in central Oregon, and a taxonomic revision was made of the four
species of section Eunanus reported from Oregon--M. nanus, M.
cusickii, M. clivicola Greenm. and M. jepsonii Grant. Mimulus...
The Brassicaceae, Mustard Family, is a well marked natural
family, whose tetramerous flowers, tetradynamous stamens, and
distinctive bi- carpellary fruits, clearly distinguish it from related
families. It is a large family of some 3, 000 recognized species and
over 300 genera. Although numerous attempts have been made over
the past...