sorus

noun2

1. •
   Any reproductive structure, in some lichens and fungi, that produces spores.
2. •
   A cluster of sporangia on the edge or underside of a fern frond.

   • AGLAOMORPHIA, [...] Sori non-indusiate, rotundate, [...] Fronds coriaceous, dimorphous, the sterile sessile querciform, brown rigid; [...] — 1857