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Abstract Detail


Systematics Section

Holman, Garth [1], Del Tredici, Peter [2], Havill, Nathan [3], Campbell, Christopher [4], Lee, Namsook [5].

Affinities of a new species of Tsuga (Pinaceae) from Ullueng island, South Korea.

Tsuga plants from Ulleung island in South Korea are distinct from other species of hemlocks based on molecular, morphological, and ecological evidence. Ulleung island has 30 endemic species of angiosperms, but no endemic gymnosperms have been described. Ulleung hemlocks have previously been treated as T. sieboldii, based on their hairless twigs and geographic proximity. DNA sequences from nearly complete chloroplast genomes and nuclear genes of the Ulleung hemlock, T. chinensis, T.diversifolia, and T. sieboldii show the Ulleung hemlock is more divergent from its closest relative, T. diversifolia, than T.chinensis is from its close relative, T. sieboldii. Based on three seasons of phenological data for the Ulleung hemlock and seven other species of Tsuga grown in a common garden experiment, the Ulleung hemlock breaks bud early in the season and has a long growing period, which maybe adaptations to a warm-temperate coastal environment. The sterile bracts at the base the ovulate cone scales of the Ulleung hemlock have broad,sub-denticulate margins and abidentate mucro that is broader than that of T.diversifolia and less denticulate than that of T.sieboldii. Although chloroplast sequences coalesce for all species,all four sampled plants of T. diversifolia possess divergent copies of ITS that are strongly supported either as sister to the Ulleung hemlock or as part of a clade with T. chinensis and T. sieboldii. This incongruence between chloroplast and nuclear phylogenies suggests that T.diversifolia may be of hybrid origin, with the chloroplast (which is paternally inherited in Pinaceae) coming from Ulleung hemlock and either T.chinensis or T. sieboldii as the ovulate parent. Our finding ssupport treatment of the Ulleung hemlock as a species that is sister to T.diversifolia.

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1 - University Of Maine, School Of Biology And Ecology, 5735 Hitchner Hall, Orono, ME, 04469, USA
2 - ARNOLD ARBORETUM, 125 ARBORWAY, JAMAICA PLAIN, MA, 02130-3519, USA
3 - USDA Forest Service, Northern Research Station, 51 Mill Pond Rd., Hamden, CT, 06514, USA
4 - University Of Maine, Department Of Biological Sciences, 261 HITCHNER HALL, ORONO, ME, 04469-5735, USA
5 - Ewha Womans University, Life Sciences, Seoul, 120-750, KOREA

Keywords:
Ulleung island
endemic
Phylogeny
plastomes
Tsuga.

Presentation Type: Oral Paper:Papers for Sections
Session: 04
Location: Lindell B/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 10:15 AM
Number: 04007
Abstract ID:690


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