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Abstract Detail



Biogeography

Saghatelyan, Anna [1].

Geographical Connections of the Vascular Flora of Edwards Plateau, Texas.

Edwards Plateau of Texas lies on the boundary of the N American Eastern and Western Regions and the Madrean and Boreal Floristic Subkingdoms. The flora of the elevated portion of the plateau comprising 1705 vascular species was analyzed and classified into 20 geographical elements. Recent phylogenetic literature was then searched in an attempt to reveal patterns of historical migrations and geographical connections of the species of major clades. Among species of the largest family Asteraceae (249 sp./99 gen.) one half are in the largest North American Heliantheae Alliance, which together with some other clades of the family have African or Central/South American connections, and have had either Mediterranean to Mesoamerica to North America, or Africa to South America to North America dispersals of their ancestors. The Poaceae (202/72) has 66% of its species in the tropical to warm temperate subfamilies. The majority (73%) of all the Fabaceae (132/42) have connections with Madrean/Mesoamerican, Tethyan, or South American radiations. The Old World Tethyan as well as southern Hemisphere legume genera of the flora in most cases used transatlantic crossing. Half of the Euphorbiaceae (70/12) species are in the Euphorbioideae, mostly in the Euphorbia subgenus Chamaesyce which represents the largest New World radiation within the Old World-centered genus Euphorbia. The other two subfamilies have their species in tropic/subtropical, mostly American genera. The Cyperaceae (70/12), unlike that in more temperate floras, has the proportion of temperate and subtropical species in the Edwards Plateau flora shifted towards tropic/subtropical/warm temperate ones. Middle sized families Lamiaceae (42/12), with the only lrge genus Salvia and Brassicaceae (38/14) are more prominent in mostly Tethyan Old World floras, where their major centers of diversity lie. To the contrary, the Plantaginaceae (33/10) belong to the mainly South and Central American clades with the basal genera in Mesoamerica and a pattern of a Madro-Tethyan disjunction. In general southern and eastern connections prevail in the flora and transatlantic crossing, as well as south/north American bidirectional migrations are more characteristic of its species. The flora belongs to the North American Eastern Region.

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1 - McMurry University, McMurry Station Box 368, Abilene, TX, 79697, USA

Keywords:
Texas
flora
geographical connections
migrations
floristic analysis.

Presentation Type: Oral Paper:Papers for Topics
Session: 50
Location: Magnolia/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 3:45 PM
Number: 50009
Abstract ID:947
Candidate for Awards:None


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