The Geography of Phytochemical Races

2.7 North and Central America 115
Fig. 2.72 Map of Chrysosplenium
glechomaefolium
populations. “Yes”
populations have the
2-hydroxyfl avonol, “no”
populations do not. “Yes/No”
represents a general area
where both types occur (but
not mixed)
the other three fl avones, although the nature of glycosylation varied among them.
Other than to point out the obvious correlation with latitude, with the obvious exception
of the apparently overlapping populations in the center of the species’ range, the
authors offered no suggestion as to why this polymorphism might exist. So far we
are unaware of any other differences among populations of C. glechomaefolium have
been reported. It is interesting to speculate, however, that the north–south differentiation
parallels that seen in other taxa whose different biochemical profi les have been
discussed in terms of population retreat and advance in response to Pleistocene glaciation
(Soltis et al., 1997).