noun
- the small, flat, heart-shaped structure that develops from a fern spore and bears the reproductive organs
Usage: botanical
Examples
- The prothallium is the gametophyte stage in the fern life cycle.
- Students examined the tiny prothallium under a microscope in botany class.
- The prothallium produces both male and female reproductive cells.
- After fertilization occurs on the prothallium, a new fern plant begins to grow.
- The green, leafy prothallium is much smaller than the mature fern.
- Moisture is essential for the prothallium to complete reproduction.