The Geography of Phytochemical Races

7.10 Tradescantia (Commelinaceae) 297
Fig. 7.5 Compounds 608–610, fl avonoids of Tradescantia
about 0.25, a frequency of 6-hydroxylated fl avones of about 0.12, a frequency
of C-glycosylfl avones of about 0.65, and the absence of B-ring trihydroxylated
compounds. Mexican taxa exhibited 6-hydroxyfl avones at a very high frequency,
C-glycosylfl avones at a frequency of about 0.30, and a low level of trihydroxylated
compounds, but, signifi cantly, lacked both fl avonols and the sulfated cinnamic
acids. Taxa from South America were rich sources of C-glycosylfl avones (frequency
of 1.0), but had only low frequencies of trihydroxylated compounds and
sulfated acids, and lacked 6-hydroxylated fl avones and fl avonols altogether. As has
been pointed out in numerous other examples in this review, these kinds of data are
very diffi cult to interpret on their own; phylogenetic hypotheses are needed before
further progress can be made.