Presentation Title

Taxonomic distinction between Psoralidium tenuiflorum and P. floribundum (Fabaceae)

Advisor Information

Mark Schoenbeck

Location

Dr. C.C. and Mabel L. Criss Library

Presentation Type

Poster

Start Date

4-3-2016 10:45 AM

End Date

4-3-2016 12:15 PM

Abstract

Clear delineations of species are important for conservation, land management, and ecological investigations. Individuals of the plant species Psoralidium tenuiflorum (wild-alfalfa; Fabaceae) vary quite broadly in morphological characters such as leaf and stem size and quantity of flowers produced per plant, and the variants grow in separate populations with little overlap. The great morphological variation has resulted in conflicting ways of reporting on the species in the scientific literature. Some researchers describe two varieties (or subspecies) of Ps. tenuiflorum and others divide the varieties into two separate species – Ps. tenuiflorum (smaller/fewer flowers) and Ps. floribundum (larger/more flowers). The question remains, “Should these morphological variants be distinguished as separate species?” My project involved two primary lines of investigation – morphological and phylogenetic. Over two summers, I collected multiple plant specimens and leaf tissue for DNA extractions from six sites across Nebraska (three in the southeast and three in the west). I measured and compared 11 morphological characters on 52 specimens. I sequenced 72 chloroplast and eight mitochondrial genes, plus three nuclear ribosomal regions using the next-generation Illumina sequencing platform. Combining these data with sequences from previous work and GenBank data, I estimated the phylogenetic placement of the two morphological variants of Psoralidium. They are closely related but definitely separated on the evolutionary tree. Both the phylogenies and the morphological comparisons revealed clear distinctions between the morphological variants, supporting their separation into two species, Ps. tenuiflorum and Ps. floribundum.

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COinS
 
Mar 4th, 10:45 AM Mar 4th, 12:15 PM

Taxonomic distinction between Psoralidium tenuiflorum and P. floribundum (Fabaceae)

Dr. C.C. and Mabel L. Criss Library

Clear delineations of species are important for conservation, land management, and ecological investigations. Individuals of the plant species Psoralidium tenuiflorum (wild-alfalfa; Fabaceae) vary quite broadly in morphological characters such as leaf and stem size and quantity of flowers produced per plant, and the variants grow in separate populations with little overlap. The great morphological variation has resulted in conflicting ways of reporting on the species in the scientific literature. Some researchers describe two varieties (or subspecies) of Ps. tenuiflorum and others divide the varieties into two separate species – Ps. tenuiflorum (smaller/fewer flowers) and Ps. floribundum (larger/more flowers). The question remains, “Should these morphological variants be distinguished as separate species?” My project involved two primary lines of investigation – morphological and phylogenetic. Over two summers, I collected multiple plant specimens and leaf tissue for DNA extractions from six sites across Nebraska (three in the southeast and three in the west). I measured and compared 11 morphological characters on 52 specimens. I sequenced 72 chloroplast and eight mitochondrial genes, plus three nuclear ribosomal regions using the next-generation Illumina sequencing platform. Combining these data with sequences from previous work and GenBank data, I estimated the phylogenetic placement of the two morphological variants of Psoralidium. They are closely related but definitely separated on the evolutionary tree. Both the phylogenies and the morphological comparisons revealed clear distinctions between the morphological variants, supporting their separation into two species, Ps. tenuiflorum and Ps. floribundum.