Analysis of morphological and anatomical characteristics of Isoetes using isoetes tennesseensis

The three known populations of Isoetes tennesseensis were examined to document and analyze their morphological and anatomical characters. Characters examined included velum coverage, lacunae, leaf form and size, sporangial wall cells, and ligule and labium morphology. Three types of morphological patterns were found: stable, variable, and dimorphic. The discovery of dimorphism between mega- and microsporophylls for velum coverage, velum length, sporangium size, and ligule shape is of particular interest. This study presents a model for future work designed to complement current species descriptions and it establishes a baseline for morphological comparisons with other Isoetes. © 2005, by The New York Botanical Garden Press.