Abstract Detail



Systematics

Hildebrand, Terri [1], Al-Shehbaz, Ihsan A. [2].

Terraria haydenii (Thelypodieae, Brassicaceae), a New Mustard Genus and Species from the West Desert Region of North America’s Great Basin.

The West Desert region of the Great Basin occurs in the states of Utah and Nevada (U.S.A.).  It describes an ecosystem dominated by shadscale and sagebrush species as well as mountains covered with juniper (Juniperus osteosperma) and piƈion pine (Pinus monophylla).  Typical of the Great Basin, internal mountain ranges dissect the West Desert region, including the San Francisco and Wah Wah Mountains.  During the 2012 growing season, a flora inventory of the region was implemented to determine if federally managed plant species grew on public lands in the region.  During this inventory, discovery of a previously undescribed plant growing in the Wah Wah Mountains occurred.  Our study reports the results from morphological and evolutionary investigations of this novelty, as well as preliminary ecological observations. The original discovery site was located on 13 June 2012 with plants growing on a hillock of Ordovician limestone with white conglomeratic quartzite.  Another population of the species was located in 2013 on Spider Marble Mound, some 1.6 km from the original discovery site. Soil analysis of collections from both locations revealed extremely alkaline soils (mean pH=9.0).  The Spider Marble Mound site had significantly greater organic matter and potassium than the original discovery site, but lower percent water content. Chromosome counts of meiotic cells in diakinesis revealed a diploid chromosome number of 2n = 20.  Maximum parsimony analyses of rbcL sequence data (1268 bp) collected from the plant, combined with data from 72 other members of Brassicaceae (GenBank), revealed the new plant was sister to members of tribe Thelypodieae and Streptanthus carinatus.  This group occurred in a larger clade represented by members of tribes Sisymbrieae, Brassiceae and Schrenkiella parvula.  The trnL–F intron sequence from the new species contained a 199 bp inversion making it 544 bp in length compared to the 366 bp matrix produced by aligning trnL–F data from 21 other members of Thelypodieae (GenBank).  Parsimony analysis of Thelypodieae using trnL–F data clearly placed the new species sister to Argentinean Parodiodoxa chionophila. Currently, the two populations in the Wah Wah Mountains represent the known distribution of Terraria haydenii.  Evidence of herbivory on the leaves, and very small Coleoptera observed on the plants suggest T. haydenii plants may play an important ecological role in this harsh microenvironment characterized by temperature extremes and low moisture levels.  


1 - Montana State University Northern, Biology, 300 13th Street West, Hagener Science Center 205, Havre, MT, 59501, United States
2 - Missouri Botanical Garden, P. O. Box 299, St. Louis, MO, 63166-0299, United States

Keywords:
Cruciferae
Hesperidanthus
Utah
rbcL
trnL-F.

Presentation Type: Poster
Number: PSY008
Abstract ID:333
Candidate for Awards:None


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