Definition of prothallus
1 : the gametophyte of a pteridophyte (as a fern) that is typically a small flat green thallus attached to the soil by rhizoids
2 : a greatly reduced structure of a seed plant corresponding to the pteridophyte prothallus
Learn More about prothallus
Seen and Heard
What made you want to look up prothallus? Please tell us where you read or heard it (including the quote, if possible).