Examining Morphometric Variation in Lomatium cous

AUTHOR: Reina Watkins
FACULTY: Donald Mansfield
DEPARTMENT: Biology

ABSTRACT

The evolution of the Perennial Endemic North American (PENA) clade of Apiaceae is convoluted and poorly understood due to polyphyly, the high possibility of incomplete lineage sorting, parallelism, and morphological homoplasy among species. Intraspecific morphological characters have displayed high variation, encouraging botanists and researchers alike to suggest that there exist several distinct groups within one species, defying the definition of species. This present study focuses on the morphological characters of Lomatium cous since it has great variation and has been thought to contain several distinct groups. We hypothesize that there exists a distinctness within Lomatium cous through morphological characters from an evolutionary force. Herbarium specimens spanning from Northern Wyoming, Northern Nevada, Eastern Oregon, Southeastern Washington, and covering Idaho were used in this study. Specimen characters were measured to the nearest hundredth of a millimeter or coded binomially. The resulting data table was logarithmically transformed, normalized, and analyzed with a principal components analysis (PCA) and a linear discriminates analysis (LDA) in the program PAST 4.08. The results of the PCA revealed a tendency for the Lomatium cous found in Southeastern Oregon, Southwest Idaho, and Northern Nevada to dissociate from specimens from other regions. The results of the LDA determined the validity of the distinctness revealed in the PCA. This study looks to utilize mechanisms of evolution such as broad geographic isolation and climate variation to explain the trends found in the results. This study adds to the PENA study currently funded by an NSF grant to elucidate the evolution of the clade.