The Geography of Phytochemical Races

64 2 Examples Within Continents
Fig. 2.39 Compounds 131–138 from Cymbopogon distans
to 60% piperitone, with lesser amounts of β-ocimene [137]. The fourth chemotype,
found at Almora at 1800 m elevation (Loharkhet), was characterized by the presence
of 48% sesquiterpene alcohols, for example, derivatives of eudesmol [138],
and other related compounds. The authors pointed out that chemotypes 1 and 3
were separated by only fi ve miles, chemotypes 2 and 3 by about 80 miles, and are
over 100 miles from the populations that afforded chemotypes 1 and 2. They also
noted that, whereas chemotypes 1, 3, and 4 have been observed at other sites in this
region, chemotype 2 seems to be restricted to the region around Munsiyari. These
profi les appear to be independent of environmental factors, since plants grown in a
common garden produced oils of the same composition as those collected from the
fi eld. No immediate explanation for this level of variation comes to mind, especially
in view of the comparative constancy of oil composition in other species.
2.5.3 Cupressus or Chamaecyparis? (Cupressaceae)
Gadek and Quinn (1987) demonstrated the usefulness of fl avonoids, in particular
bifl avonoids, in addressing the question of generic placement of Cupressus funebris
Endl. Geography became a factor in this otherwise straightforward chemotaxonomic
exercise because earlier work on wood tropolones (Zavarin et al., 1967b; more on
these compounds below) was done on material obtained from northern India, which
lies outside the accepted central Chinese range of C. funebris. Furthermore, certain
morphological features of C. funebris, particularly dimorphic leaves, small cone
size, and low seed number, suggested that Chamaecyparis might be the better taxonomic
home for this taxon. Based upon the knowledge that bifl avonyl profi les of
Cupressus and Chamaecyparis are different, Gadek and Quinn (1987) examined
a specimen of C. funebris for these compounds. The outcome of the analysis was