Today, due to heavy rain I could not arrange to go out for field study. So, I started searching for something in my own campus. In the backyard of my school I find some mosses in their sporophyte stages. When I bring them for study, I totally amazed after seeing stomata in their sporangium. After seeing that I have reviewed some research article and find that this early land plants have stomata only in the sporangium.
Stomata are one of the key organs of gaseous exchange in land plants. This consist of two guard cells and a pore between that leads to an internal cavity. Mosses are the earliest land plants to have stomata, but unlike those in all other plants, bryophyte stomata are located exclusively on the sporangium of the sporophyte (MERCED & RENZAGLIA, 2017).
This is really a foldscopic achievement to evaluate the role of stomata in ascertaining the evolutionary history of land plants.
Cheers,

References:
MERCED AMELIA & KAREN S. RENZAGLIA (2017):Structure, function and evolution of stomata from a bryological perspective; Bry. Div. Evo. 39 (1): 007–020 http://www.mapress.com/j/bde