Through the use of molecular techniques, several different types of fusiform and twisted-fusiform microchlorophyte algae (Monoraphidium, Ankistrodesmus, etc.) have been characterized from samples taken from lakes and ponds of Itasca State Park, Minnesota. PCR-RFLP analysis of 18S ribosomal RNA genes was used to categorize 29 different isolates from the Itasca State Park lakes into 9 different types. 18S ribosomal DNA sequences were determined for one isolate from each type for phylogenetic analysis. Light microscopy was used so that morphological characteristics as well as molecular characteristics can be compared and contrasted. The morphological characteristics were consistent for each PCR-RFLP type. Further discussion will include comparisons of the distribution and diversity of these organisms from Itasca State Park to those from Arrowwood National Wildlife Refuge, North Dakota.

Key words: algal diversity, Ankistrodesmus, Chlorophyceae, Kirchneriella, Monoraphidium