The Geography of Phytochemical Races

60 2 Examples Within Continents
Fig. 2.36 Map of Lavandula stoechas sites on Crete
2.4.9 Juniperus phoenicea (Cupressaceae)
Rezzi et al. (2001) described an examination of the essential oils of Juniperus
phoenicea L. subsp. turbinata (Guss.) Parl. Nyman (syn. J. phoenicea subsp. lycia
Auct. = J. turbinata Guss.) growing on Corsica (Fig. 2.37). Individual plants were
collected from six sites representing typical habitats and were analyzed for their terpene
fraction; the major components of which were identifi ed as α-pinene, α- and
β-phellandrenes [129, 130, respectively], α-terpineol acetate, 3-carene [97], and
myrcene [40]. Cluster and discriminant analyses revealed two groups of populations
that could be distinguished based on contents of α-pinene, β-phellandrene,
and α-terpinyl acetate with α-pinene as the major discriminating factor. Plants
exhibiting the two chemotypes, identifi ed as Group I with high α-pinene and low
β-phellandrene, and Group II with lower α-pinene and higher β-phellandrene,
grew intermixed but in different ratios at different sites. For example, Group I and
Group II plants were found to occur in a ratio of 7:1 at a site near Porto-Vecchio
(southeastern coast), whereas a ratio of 1:9 was observed at two sites, one near
Borcaggio (northern peninsula) and one near Ajaccio (southwestern coast). The
population at Bonifaccio (southern tip of the island) exhibited a 1:1 ratio of the two
types. Whereas there seem to be no relationship of these two types with geography
of the island, or with habitat differences, relationships with populations on the mainland
were noted. Thus, Group I plants bear closest similarity to α-pinene-rich oil
from J. phoenicea s. st. collected in Greece and Spain, whereas Group II plants have
an α-pinene-poor oil that bears more similarity to the oil from plants growing in
Portugal and also in some parts of Spain. There clearly seems to be some diffi culty
with taxonomic details in this system, as the authors noted in their discussion.