Isoetes plants have bilaterally symmetrical stems with a system of lobes and furrows. The stem does not elongate and the plant produces only fertile leaves, or sporophylls.

Isoetes is heterosporous, producing both micro- and megasporangia. 

In this photograph you can see numerous young leaves being developed in the center of the plant, at the shoot apex, with the older leaves overarching younger ones.

The large sacs at the top of the photo are the sporangia: All of them are microsporangia with dense masses of microspores except the one on the far right, which is a megasporangium. 

Click for: leaves xs,  ligule, root xs, microsporangium