Buckiella undulata may be found along streams and in coniferous forests. Substrata include humus, rotten logs, moist soil and rock (rarely).
Buckiella undulata exhibits a pleurocarpous growth form. The shoots are irregularly-branched and distinctively flattened.
Some common names for Buckiella undulata include “snake moss”, “wavy cotton moss” and “tongue moss”.
As suggested by its specific epithet, the leaves of Buckiella undulata are undulate, meaning they are “wavy”.
A double costa extends less than a quarter up the leaf from the base. Laminal cells are elongate.
The stem has a central conducting strand and a cortex of parenchymal cells. An epidermis encloses the stem.
Mature sporophytes are red-brown and can be found in spring.
At maturity, the red-brown sporangia are grooved. Peristome teeth are white.
The seta is grooved and long when fully mature.