Marginal cells are elongate and entire. The cells of the costa are also elongate. Generally, the laminar cells are isodiametric in shape.
Along with stereids, the costa contains a central conducting strand.
Located at the apex of the male gametophyte are a dark centre of antheridia and paraphyses. A rosette of perigonial leaves surround the reproductive structures. These leaves make up the perigonial head. This arrangement works as a splash cup mechanism to disperse sperm. The antheridia turn red-brown after the sperm have been released.
A longitudinal section through a perigonial head reveals antheridia resemble brown sacs, while paraphyses are uniseriate, sterile, and almost clear.
The sporophytic generation develops parasitically on the female plants. If the sporophyte is gently pulled off of the female plant, archegonia and paraphyses may be seen around the foot of the sporophyte.
Rhizomnium glabrescens is dioicous, the sexual condition in which male and female reproductive structures are located on separate plants.
Once spores are released and dispersed from the sporangium, they may eventually begin to germinate under optimal conditions. Spores germinate and produce protonema. Leafy gametophytes may begin to grow from protonema when the conditions are optimal.