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Abstract Detail


Systematics Section/ASPT

Doucette, EricThomas [1], Burgess, Michael [2], Cushman, Kevin [3], Frye, Christopher [4], Campbell, Christopher [5].

Reinterpreting Amelanchier arborea (Rosaceae).

Amelanchier arborea(Michx. f.) Fern. as currently circumscribed is wide-ranging in eastern North America, both as diploids and tetraploids. The diploid is a member of what we refer to as the arborescent clade, with A. laevis Wieg. and A. canadensis (L.) Medik. This clade is strongly supported by DNA sequence data and its members have many flowered, elongate inflorescences, normally glabrous ovary summits, and (at least in some individuals) an arborescent habit. Diploid A. arborea is morphologically diagnosable by the character suite of strongly recurved sepals, acuminate leaf apices, and sparsely to moderately hairy mature leaf blades. Our field work has identified numerous tetraploid individuals that conform more or less closely to this general morphology. However, our data show that many arborea-liketaxa historically allied with A. arboreaare of hybrid origin. Morphology and data from the second intron of a copy of the LEAFY gene, for example, show that A. sera Asheis a hybrid between A.arborea and A. canadensis. Similarly,a taxon from central Maine that we refer to as A. "oligoflora" (amicrospecies) contains A. arborea andA. humilis Weig. genomes.Morphological and limited molecular evidence indicate that A. alabamensis Britton nests with A. arborea from Georgia.Hairy ovary summits and extremely narrow petals, which diagnose A. alabamensis, can be found sporadically throughout the range of A.arborea. In phylogenetic trees based on ETS, ITS, and LEAFY some tetraploid A arborea individuals are linked todiploid A. arborea and/or A. laevis, A. humilis and A. canadensis. These trees suggest that tetraploid A. arborea is an assemblage of genetically heterogeneous allotetraploids of multiple origins, with some originations incorporating genetic material from outside the arborescent clade. Morphologically, A. arborea is closest to A. laevis, and we have collected cryptic hybrids between them.

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1 -
2 - University Of Pennsylvania, 16 W Highland Ave, Apt. 2, Philadelphia, PA, 19118, USA
3 - P.O. Box 143, Levant, ME, 04456, USA
4 - Maryland Wildlife And Heritage Service, 909 Wye Mills Road, PO Box 68, Wye Mills, MD, 21679, USA
5 - University Of Maine, Department Of Biological Sciences, 261 HITCHNER HALL, ORONO, ME, 04469-5735, USA

Keywords:
diploids
tetraploids
cryptic hybrids.

Presentation Type: Oral Paper:Papers for Sections
Session: 45
Location: Delaware D/Hyatt
Date: Wednesday, July 11th, 2012
Time: 9:15 AM
Number: 45006
Abstract ID:880


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