Saghatelyan, Anna .
Evidence of Madro-Tethyan connections in a comparative analysis.
Congruent distribution outlines of unrelated taxa may reveal historical patterns. Centers of diversity of progressive genera usually also are their centers of origin. Madro-Tethyan connections were considered in a comparative analysis of the floras of Trans Pecos, SW Texas, and Armenia, SW Asia. Trans Pecos flora has 1501 species in 810 genera. Distributional data for Trans Pecos genera were searched in the literature. The summary of generic distribution is: 5% cosmopolitan, 54% restricted to the Americas, 25% tropic-subtropical and only 16% north temperate. Common between the two floras are 120 north temperate genera (15% of Trans Pecos genera). They represent florogenetic elements of different origin and age. Relicts of arcto-tertiary geoflora are preserved in the mountains of the Holarctic (Acer, Juglans, Crataegus, Fraxinus, Viburnum, Mahonia and Vitis). Frigid Old World genera (Gentiana, Anemone, and Androsace) and more xerophytic (Delphinium, Arenaria) have probably evolved since the Eurasian alpine orogeny and have used the Bering Land Bridge. Now half of their species are in the Sino-Himalayan Region. Old World tethyan genera (Bering Bridge: Astragalus, Allium, Silene; North Atlantic Bridge: Helianthemum, Linum) have further diversified in parts of North America. Some common genera are more diverse in the New World (Quercus, Salvia, and Polemonium). Madro-Tethyan genera (Cupressus, Ephedra, Arbutus, Juniperus, sections of Quercus) are Tethyan and Madrean relicts. East Tethys/Gondwanan genera are Andrachne, Corydalis, and Sedum. Gondwanan/Tethys genera are Eryngium and Lotus. Nine genera are subtropic-temperate of both hemispheres (Lycium). The majority of the common genera is of the Old World origin, or has a huge center in Mexico. Western American lineages derived from the common Laurasian pool not present in Armenia are numerous. In Armenia well represented are Frontal Asian Tethyan genera (Acantholimon) and Central Asian ancient xerophytes (Salsoleae, Chenopodiaceae) absent from the Trans Pecos flora.
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paper on the analysis of the flora Armenia
1 - McMurry University, Biology, McM Station Box 368, Abilene, Texas, 79697, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Wednesday, July 30th, 2008
Time: 10:45 AM