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Abstract Detail



Systematics Section/ASPT

MCCAULEY , ROSS A [1], HAVRAN, J CHRISTOPHER  [2].

Paraphyly, hybridization, and multiple introductions in the origin and evolution of the endemic Amaranthaceae of the Hawaiian Islands (genera Achyranthes, Charpentiera and Nototrichium).

The Amaranthaceae s.str. are represented in the Hawaiian Islands by six genera and 24 species with 11 of these species, in four genera, endemic to the archipelago. Similarities in floral form and distribution have led to the development of hypotheses of origin however no explicit tests of these hypotheses have ever been made. We evaluated ten of these 11 endemic Hawaiian Amaranthaceae and compared them phylogenetically with other Pacific Basin species to understand their origins and general patterns of diversification using sequence data from the nuclear ITS and chloroplast rpl32-trnL regions.  In Nototrichium (A. Gray ex Hillebr.) Hillebr. the three species of shrubs endemic to the archipelago appear to be a monophyletic group nested within a paraphyletic Achyranthes L.  Within Achyranthes A. bidentata var. japonica Miquel, a herbaceous species with invasive tendencies distributed across East Asia appears sister to the woody Nototrichium, a finding running counter to the prevailing hypothesis of a close relationship with A. arborescens of Norfolk Island.  Within Nototrichium the widespread N. sandwicense (A. Gray) Hillebr. was shown to be paraphyletic in relation to the more restricted species of N. humile Hillebr. and N. divaricatum Lorence.  The three endemic Hawaiian species of the widespread Achyranthes appear to have been derived from two different colonization events with A. splendens Mart. ex Moq. representing one and A. mutica A. Gray and the presumed extinct A. atollensis St. John from the Northwestern end of the Hawaiian Islands representing the second.  Charpentiera, a basal member of the Amaranthaceae s.str. with unclear connections to the remainder of the family with five species endemic to the Hawaiian Islands and one in the Austral and Cook Islands was shown to be monophyletic in chloroplast data.  Nuclear data suggests gene exchange between the widespread C. obovata Gaud., C. australis Sohmer of the Austral and Cook Islands and Achyranthes mutica at the western end of the main Hawaiian Islands perhaps as the result of intergeneric hybridization. 


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1 - Fort Lewis College, Department Of Biology, 1000 Rim Drive, Durango, CO, 81301, USA
2 - Campbell University, Dept Biological Sciences, 205 Day Dorm Rd, Buies Creek, NC, 27506, USA

Keywords:
Hawaii
Amaranthaceae
Achyranthes
Charpentiera
Nototrichium
ITS
rpl32-trnL.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PSY017
Abstract ID:444
Candidate for Awards:None


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