Moss sporophytes are physically attached to and dependent on the leafy gametophyte through their entire life. During early development, the sporophyte apex is covered by the calyptra, a cap of gametophytic tissue which protects the developing capsule. The aim of this study is to examine the influence of the calyptra on sporophyte transpiration rates in mosses. We used two laboratory-grown species with different sporophyte and calyptra sizes for this study: Funaria hygrometrica Hedw. and Physcomitrium pyriforme (Hedw.) Hampe. When the calyptra was removed from the sporophyte apex, there were significantly higher rates of sporophyte transpiration compared to individuals with the calyptra present. These results provide evidence supporting the importance and influence of the gametophyte calyptra on the movement of water in moss sporophytes. Changes in transpiration, and thus the pull of water and nutrients from the gametophyte into the sporophyte, may also have downstream effects on sporophyte reproductive output.