Zamia roezlii is a species of cycad, a plant in the Zamiaceae family. It is found in Colombia and Ecuador.
Named by the Czech botanist Benedikt Roezl.
A single sperm cell from Zamia roezlii is about 0.4 mm in length and is visible to the unaided eye, being the world's largest sperm.
Read more about Zamia Roezlii: Source