The genus Juniperus in Mexico and Guatemala: Numerical and chemosystematic analysis

The variation leaf constituents (mostly terpenoids) was analyzed from each of the taxa of Juniperus in Mexico and Guatemala by numerical taxonomic methods. These results were compared with those of a previous study utilizing morphological characters. In general, the two agree on the major groups. Differences between more closely related species were more apparent with the chemical data, whereas more distantly related taxa sometimes appeared to be more closely related chemically due to the presence of a single component such as α-pinene in high concentration in each of the oils. Four large groups are apparent; the deppeanan; flaccidan; monticolan; and the oneseeded (pinchotii) complex. Some taxa (J. durangensis, J. standleyi, J.jaliscana) are still of uncertain affinities. This study confirms the morphological data indicating that J. patoniana Martínez should be reduced to a variety of J. deppeana (J. deppeana var. patoniana (Martínez) Zanoni, comb. et stat. nov). No samplestypical of J. monosperma were found in Mexico and J. monosperma var. gracilis (sensu Martinez) was found to not be closely allied with J. monosperma from the USA but has some uncertain affinities with species of the one-seeded complex. These relationships need to be examined in more detail. J. blancoi appears to be closely related to J. scopulorum. This information on the junipers of Mexico and Guatemala should prove invaluable to future studies on the evolution of the Juniperus in North America.