1. A vertical section of an antheridial receptacle of M. polymorpha, showing
  a- The structure of the stem.
  b- Rhizoids and scales.
  c- Stomata leading into air cavities.
  d. Narrow openings leading to the antheridia.
2. An antheridium enlarged-
  a-- Single layer of chlorophyll bearing cells.
  b.-- Sperm cells
3- A vertical section through the perichaetium.
4. A vertical section through a fertile disk, showing the suspended archegonia."

Courtesy of University of Iowa Libraries, Special Collections