prothallus

noun

pro·​thal·​lus (ˌ)prō-ˈtha-ləs 

1

: the gametophyte of a pteridophyte (such 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

Illustration of prothallus

• 1 antheridium
• 2 archegonium
• 3 rhizoid

Word History

Etymology

New Latin

First Known Use

1854, in the meaning defined at sense 1