1. Leaves gradually tapered to the base, elliptic in outline (widest ± at the middle).
O. pusillum
1. Leaves abruptly tapered to the base, ovate in outline (clearly widest below the middle).
O. vulgatum
All species found in Ophioglossum
Citation:
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. January 25, 2021. https://michiganflora.net/genus.aspx?id=Ophioglossum.