Here's why:
* Heterospory: Selaginella is a heterosporous plant, meaning it produces two distinct types of spores: microspores (male) and megaspores (female).
* Trilete Mark: Both microspores and megaspores in Selaginella possess a distinctive trilete mark, which is a Y-shaped scar on their surface. This mark is a result of the way the spore wall splits open during germination.
Therefore, while Selaginella does produce two different types of spores, they both share the characteristic trilete mark.
