The Geography of Phytochemical Races

78 2 Examples Within Continents
Table 2.15 Selected values for oil composition of Argentinean Minthostachys verticillata (after
Zygadlo et al., 1996)
Site Compounda β-Pine Limon Menth Puleg Carvo Thym Carva
Catamarca Prov.
Potrero trb 8.9 8.8 5.1 tr 31.8 34.0
Balcosna tr 21.1 12.9 33.3 0.2 nd nd
Sebastien
Córdoba Prov.
0.9 10.1 8.1 5.6 0.5 10.5 25.3
Candonga tr 1.4 29.2 47.0 tr nd nd
Cuesta Blanca 0.1 10.1 29.6 39.0 1.1 nd nd
Paradones
San Luis Prov.
0.4 25.0 15.8 31.2 1.0 nd nd
Merio 0.4 13.1 27.0 39.6 0.3 nd nd
Baños Pasos Malos
Tucumán Prov.
0.4 17.6 12.8 45.1 0.1 nd nd
Rancho de la Cascada 5.1 17.1 5.5 1.2 35.2 nd nd
Potreros de las Tablas 6.1 11.9 28.3 21.1 tr nd nd
a β-Pine = β-Pinene; Limon = limonene; Menth = menthone; Puleg = pulegone; Carvo = carvone;
Thym = thymol; Carva = carvacrol.
b tr = Trace amount; numbers are percentages of total oil; nd = not detected.
An example closely related to the previous case involves oil composition of
Minthostachys andina (Brett) Epling collected in central Bolivia. The study, by
Muñoz-Collazos et al. (1993), revealed that plants with the chemotype characterized
by high amounts of pulegone and menthone (at least 65%) tended to occur at
higher elevations, providing that sampling “. . . did not involve the transition zone
between the dry highlands and humid and warmer Amazonian region.”
2.7 North and Central America
2.7.1 Notholaena standleyi (Adiantaceae)
Notholaena is a genus of ferns with close relationships to Cheilanthes and Pellaea
with which they may intergrade. The genus is represented in tropical to warm parts of
the New World and includes a number of xerophytes. Notholaena standleyi Maxon,
the subject of this study, fi ts well in this category owing to its occurrence in the
dry regions of the United States and adjacent Mexico. It has been known for many
years that members of this species exhibit different colored exudates on the undersides
of their leaves. Three color forms are known, a gold-colored race, a yellowcolored
race, and a yellow–green race. The gold-colored race occurs in Arizona and
far northwestern Mexico (including Baja California) where it occurs mainly on rocks
of igneous origin. The yellow-colored race occurs more widely having been recorded