Freshwater burrowing mussels (unionids) play a vital role in freshwater ecosystems through nutrient cycling and promoting biodiversity. They have unique life histories directly related to aquatic vertebrates during an obligate parasitic larval stage, known as glochidia. Human interference has largely impacted mussel populations causing them to become the most endangered group of animals in North America. Genetic data has revealed taxonomic issues related to valve morphology, such as valve plasticity and cryptic speciation, that has caused identification issues in the field. Using both genetic and morphometric methods, I determined the phylogenetic placement of an isolated population of mussels within the tribe Lampsilini. I also investigated whether this population was a morph of a previously known Lampsilin species or if they were worthy of being treated as an evolutionarily significant unit (ESU) or an undescribed species. In addition, I expanded the known phylogeny of Lampsilin by including three species (Lampsilis fasciola, Lampsilis hydiana, Ligumia subrostrata) not included in previous phylogenies. Genetic analysis involved sequencing cytochrome c oxidase subunit 1 (COI) and 16s ribosomal RNA (rrnL) genes and producing maximum likelihood trees with bootstrap values for each gene individually and combined. Genetic results showed that an population from an isolated pond (named Junk Pond in this study) were closely related to members of the genus Ligumia (pondmussels), with Ligumia subrostrata being their closest relative. Morphologically, these Junk Pond mussels were noticeably different from other Ligumia species, so genetic and morphometric data was used to try and characterize this population of mussels from Junk Pond. The genetic distance between these two groups, measured using K2P distance method, were like the distances of other known sister species within Lampsilini. Morphometric analysis involved landmark and semi-landmark analyses to quantify the differences of the internal and external shapes of the shell, respectively, and determine differences that could be species defining characteristics. Landmark analysis results showed that Ligumia subrostrata and the Junk Pond mussels had similar internal valve structures though semi-landmark results showed differences among all groups including L. subrostrata and the Junk Pond mussels. I determined that this isolated population, due to its geographic isolation, genetic differences, variant shell morphology, and limited population size, should be treated as an ESU. The expanded Lampsilin tree showed a few differences involving Ligumia nasuta that did not support a previously published tree. Many other relationships within this phylogeny agreed with previously published works. The isolated population of the Junk Pond mussels are worthy of future research using more genetic data, such as COI, and morphometric work involving other Lampsilin members in order to conclude whether this group are worthy of being recognized as an undescribed species.

The genus Chrysopsis (Asteraceae) contains eleven species native to Florida, including the newly described species, Chrysopsis delaneyi. Populations of this endemic plant species inhabit the Lake Wales Ridge (LWR) and the Atlantic Ridge (AR) of the Florida peninsula. Differences in morphology have been demonstrated within C. delaneyi, based on their locations. My objective was to determine the relationships between the LWR and the AR populations by analysis of chloroplast sequence and nuclear sequence variation. Approximately 160 samples of C. delaneyi and its sister species C. scabrella have been collected from fifteen sites throughout Florida. Six single base differences were detected, one insertion, and one variable short duplication. A total of four haplotypes (i.e.: groups that have different combinations of polymorphisms) have been found. For the most part, one haplotype is found in LWR populations and is indistinguishable from that found in C. scabrella. Another haplotype is found primarily in AR populations and is more similar to haplotypes found in the more distantly related C. highlandsensis and C. floridana. One haplotype is found within populations of C. scabrella. The last haplotype in one AR population contains two polymorphic loci, one site is representative of the AR populations, and the other site is that of the LWR populations. Only one mixed population has been found, at the northern end of the AR range. These results are not consistent with taxonomic relationships inferred from morphological characteristics; hence the results suggest that chloroplast DNA (cpDNA) relationships may be the consequence of one or more instances of chloroplast capture.