The Geography of Phytochemical Races

54 2 Examples Within Continents
Fig. 2.33 Map of Genista sites in northwestern Italy, Elba, Corsica, Sardenia, and Provence.
Gs = Genista salzmannii, Sl = Genista lobelii
although taxonomic opinion differs as to their distinctiveness. Genista lobelii occurs
in southeastern Spain and southern France, while G. salzmannii occurs in Sardinia,
Elba, Corsica, and in the Ligurian region of western Italy (Fig. 2.33). In an alternative
view (Gamisans, 1973), G. lobelii was submerged into G. salzmannii with the
further recognition of three varieties, var. lobelii in Provence, var. lobelioides in Corsica
above 1200 m elevation, and var. salzmannii in Corsica below 1200 m. Because
morphological variation within these taxa makes identifi cation, and thus the assessment
of relationships, diffi cult, additional sources of potentially useful taxonomic
characters were sought (Kirch et al., 1995). These latter workers chose to examine
the quinolizidine alkaloids, a class of compounds that had been shown to be useful
sources of information in other legume genera, for example, Pearsonia (van Wyk
and Verdoorn, 1991) and Virgilia (Greinwald et al., 1989).
Kirch et al. (1995) examined individual plants collected in Corsica, Elba,
Sardinia, Liguria, and Provence for alkaloids and observed four groups, one characterized
by sparteine [119] (see Fig. 2.34 for structures 119–124), one characterized
by lupanine-based alkaloids [120 and 121], one that had a very low level of alkaloid
production, and one that lacked sparteine and lupanine-based compounds, but did
accumulate other alkaloids such as anagyrine [122], ammodendrine [123], and compounds
based on cytisine [124], their “outlier” group. The distribution of these four
chemotypes is presented in Table 2.10.
These workers concluded that the chemical differences among populations from
the various sites were too small to support recognition of two species, pointing
to the lack of correlation between morphological features and alkaloid chemistry.
They noted as well that the “outlier” chemistry could be the result of developmental,