Abstract
Stem xylem terpenes of 75 pine populations were studied to determine relationships among taxonomic entities. Typical
Pinus patula populations occurring in areas north and west of Oaxaca, Mexico, had very high proportions of 3-phellandrene and low proportions of other constituents. Terpene compositions of populations of variety longipeduncalatain northern Oaxaca were similar to that of the typical variety, while those of populations in southern Oaxaca resembled that of P. aecunumanii.Typical P. lecunumaniifrom populations in Chiapas (Mexico), Guatemala, and southwestern Honduras contained high proportions of a-pinene, carene,limonene, and p-phellandrene. Populations in southern Mexico, Guatemala, Honduras, Nicaragua, and Belize that contained very high proportions of a-pinene and low proportions of other constituents were judged to be typical P. oocarpa. Other populations in Guatemala, Honduras, and Nicaragua tended to resemble both P. oocarpa and P. lecunamaniiand were judged to be atypical P. oocarpa. Our results suggest that the two species hybridize at middle elevations, where they occur together. Other researchers regard the atypical P. oocarpa populations as P. oocarpa, P. palula ssp. tecanamanii,or P. oocarpa var. ochoterenae. Most atypical P. oocarpa were more similar to P. oocarpa than to P. lecunrmanii.They were definitely more similar to P. oocarpa than to P. patala and hence should not be referred to the latter taxonomically. P. caribaea var. hondurensis trees differed from others mainly in that they contained high proportions of a-pinene and /3-phellandreneand low proportions of other constituents. Hybridization with P. oocarpa occurs where the two species occur together at low elevations.
Keywords
Monoterpenes,
taxonomy
Citation
Squillace, A.E.; Perry, Jesse P., Jr. 1992. Classification of
Pinus patula, P. tecunumanii, P. oocarpa, P. caribaea var.
hondurensis, and Related Taxonomic Entities. Res. Pap. SE-285. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 23 p.