Rattlesnake fern gets its name from the fertile section of frond, which is reminiscent of a rattlesnake's rattle. The fertile section is green when young and bright yellow when the spores are mature.
- Synonyms: Botrypus virginianus
- Family: adder's-tongue (Ophioglossaceae)
- Habitat: rich woodlands
- Height: 8-30 inches
- Location of spores: separate fertile portion of frond, which branches from the sterile portion at the base of the blade
- Petiole (leaf stalk): smooth, round, and pink at the base
- Growth pattern: single leaf
- Persistence: deciduous
- Origin: native
Photographed in Montgomery County, Pennsylvania in early June.