The protective covering of a seed.
Seedcases keep seeds safe and help them grow.
Examples:
The seedcases of the sunflower are big and easy to see.
I found some seedcases on the ground.
The seedcases protect the seeds from harm.
The squirrel collects seedcases for the winter.
The seedcases are like a cozy house for the seeds.
The seedcases open up when it's time for the seeds to grow.