The rattlesnake fern (Botrychium virginianum) belongs to the family Ophioglossaceae. It is a perennial pteridophyte and distributed to various parts of Japan, the Korean Peninsula, China, South Asia, Europe, North America to Central and South America. This fern grows in mountain forests and is 25 to 70 cm tall. It is summer green and bears fertile fronds from May to June. First of all, the leaf has a single stem (phyllomophore), the tip of which branches into sterile fronds and fertile fronds. The sterile fronds spread horizontally and split into tri-pinnnate or quatri-pinnnate compound. The fertile fronds are erect upwards and are like panicles on the stalk of 10-30 cm in length.