Leucanthemum vulgare, ox-eye daisy (photo copyright S. Shamoff). 
varieties and subspecies to species status. Similar differences oc¬ 
cur at the generic level, and we particularly had to deal with the 
recent tendency among Asteraceae specialists to divide some long- 
established, polymorphic genera into numerous smaller, more 
sharply defined genera, which often have novel and unfamiliar 
names. 
The taxonomic literature that we surveyed comprises, first 
of all, the “standard floras" for the geographical region that in¬ 
cludes Oregon, and secondly, the numerous research papers and 
taxonomic revisions published in scientific journals. A peculiar 
feature of our selected floras is that the taxonomy of Asteraceae 
is dominated by the work of a single person, the late Dr. Arthur 
Cronquist. Renowned for his expertise with this plant family, 
Cronquist wrote the treatments for Vascular Plants of the Pacific 
Northwest, Part 5 (1955), Flora of the Pacific Northwest (1973), 
and Intermountain Flora, Volume 5 (1994), as well as major sec¬ 
tions of Illustrated Flora of the Pacific States, Vol. 4 (1960). Fur¬ 
thermore, Morton E. Peck, in his Manual of the Higher Plants of 
Oregon (edition 2, 1961) often followed Cronquist's lead in the 
taxonomy of this family. Only in the multiple-authored The Jepson 
Manual: Higher Plants of California (1993) do we find signifi¬ 
cant divergences from Cronquist's classification of Asteraceae 
genera and species in the Pacific Coast region. 
Arthur Cronquist was one of America's leading botanists, 
and his floristic works are admired for their thoroughness, de¬ 
tail, and practical taxonomic approach. Nonetheless, one also 
has to consider the many recent monographs and taxonomic 
papers about Asteraceae written by other individuals, who them¬ 
selves are specialists on this family. In reviewing Cronquist's pub¬ 
lications, it seems that once he had studied a particular group 
and made conclusions as to how best to circumscribe its genera 
and species, he was reluctant to make any changes based on later 
publications by other workers. With few exceptions, Cronquist 
stuck by his own original observations, and he therefore repeated 
essentially the same taxonomic treatments from one flora to the 
next. For the Oregon Vascular Plant Checklist, we balanced 
Cronquist's views against those of other authors, a task that was 
facilitated by the divergent treatments already published in The 
Jepson Manual. In many cases our choice of names differs from 
Cronquist's, as reflected in the synonyms (i.e. names we chose 
not to use) listed in Table 1. 
The greatest number of nomenclatural differences are with 
older floras, such as Peck's Manual of the Higher Plants of Oregon 
(220 name changes in Asteraceae) and the Abrams' Illustrated 
Flora of the Pacific States (209 changes). In Hitchcock and 
Cronquist's Flora of the Pacific Northwest, which was published 
28 years ago, 171 names have been changed (Table 1). The ge¬ 
nus name has been changed in about one fourth of these; variet¬ 
ies or subspecies are submerged in one third; and the rest consist 
of species name changes and changes in taxonomic rank (e.g. 
varieties changed to subspecies, or elevation of varieties to spe¬ 
cies). 
While assembling the Checklist, we examined all the Or¬ 
egon collections of Asteraceae housed at Oregon State Univer¬ 
sity. Approximately 18,000 specimens were examined. For each 
genus, we tried to match existing herbarium specimens against 
the keys and descriptions in the reference floras and in any mono¬ 
graphs written since about 1960 (i.e., since the publication of 
Peck's Manual and of Illustrated Flora of the Pacific States). Many 
specimens were found to be misidentified, and in some cases the 
misnamed collections were of species not previously recorded for 
the state. It was particularly helpful to find specimens that had 
been annotated by specialists; e.g. species of Grindelia (gumweeds 
and gumplants) annotated by Meredith Lane, Machaeranthera 
(asters) by B. L. Turner, Antennaria by G. L. Stebbins, Filago 
(filagos) by James Morefield, Senecio by T. M. Barkley, and so 
on. 
By comparing specimens with published descriptions, we 
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