Selaginella
also forms Megaspores in Megasporangia. There are only Four Megaspores in each Megasporangium. The Megaspores are large compared to the
Microspores. The four Megaspores contain the same biomass as all of the Microspores. This
accounts for the size disparity. Why might this be
advantageous for successful sexual reproduction?
The Sporangia occur in the leaf axils. There are no obvious differences between the leaves which bear
Megasporangia or Microsporangia. However, a leaf associated with a Megasporangium is properly called a Megasporophyll. A Microsporophyll would be a leaf associated
with a Microsporangium.
There is usually a color
difference between Megasporangia and Microsporangia. Due to the size of the Megaspores, the outline of the Megasporangium may
be distorted, as well. There are various distribution patterns for Micro &
Megasporangia in the cones. They are NOT randomly arranged.