The Geography of Phytochemical Races

114 2 Examples Within Continents
Fig. 2.71 Compound 229 from Larrea tridentata. Compounds 230–233, fl avonoids from Chrysosplenium
glechomaefolium. Compounds 234–236, fl avonoids from Quercus rubra
along the western coast of North America from the Olympic Peninsula of Washington
south through Oregon and into northern California. (It was not possible to verify these
reports of its occurrence in British Columbia.) It generally occurs not only in wet habitats
west of coastal mountain ranges throughout its range, but it is also known from
higher elevations in mountains in central Oregon (Mary’s Peak, Benton/Lincoln Counties).
An examination of fl avonoids of specimens representing the range of the species
(Bohm and Collins, 1979) revealed several O-methylated fl avonols the aglycones of
which were identifi ed as 5,6,3′,4′-tetrahydroxy-3,7-dimethoxyfl avone [230], 5,3′,4′trihydroxy-3,6,7-trimethoxyfl
avone [231], 5,6,3′-trihydroxy-3,7,4′-trimethoxyfl avone
[232], and 5,2′,5′-trihydroxy-3,7,4′-trimethoxyfl avone [233] (see Fig. 2.71 for
structures 230–233). All of these compounds occurred as glucosides, with the sugar
attached at the 2′-position in the last named compound and at 6′ and/or 4′-positions
in the others. The observation of note is the presence of the 2′-hydroxy compound in
plants from only six of the 13 sites from which collections were made. Plants possessing
this fl avonoid occurred in the more northerly sites—those from Washington and
northern Oregon—whereas, the plants lacking this compound occurred in California
and southern Oregon (Fig. 2.72). The two pigment types overlapped in central coastal
Oregon, although the populations sampled had either one or the other type. No population
was found that had both fl avonoid types although the sampling was not extensive
enough to place this conclusion on strong ground. All populations sampled had