The biodiversity of species in the diatom genus Brachysira was examined in 31 oligotrophic and acidic lakes situated in the Ocala National Forest in north-central Florida. Brachysira was found to be especially abundant and morphologically diverse in this region as compared to previous studies of diatoms in the United States. I used scanning electron microscopy to critically examine the morphological structure of this diverse array of taxa and various multivariate statistical analyses to aid in species determinations. A representative sample of cleaned frustules from each lake was identified and characterized using measurements of length, width, form, striae density, pore arrangement, and other distinguishing structural features. Principle component analysis (PCA) identified significant morphological characteristics, while discriminant analysis (DA) produced models to aid in the delineation of species. Additionally, I quantified the morphological features of over 200 Brachysira specimens representing 13 taxa from recent relevant publications. This data created a complimentary DA model used to classify over 300 specimens from the Ocala lakes and to aid in final species determinations. Both statistical and qualitative results confirm that there are 8 distinct taxa in these lakes. This taxonomic information will be correlated with the chemical and physical properties of the lakes and eventually compared with Brachysira specimens in other lake regions along the east coast of the United States to better understand the interaction of morphological and ecological variation.