This species is an acrocarpous moss and its shoots can either be irregularly branched or unbranched.
Here is a picture of an isolated antheridium of Andreaea nivalis.
This moss is commonly named “toothless moss” due to the fact that it does not have any peristome teeth. Instead, the sporangium has four (or more) lines of dehiscence that surrounds a dome-shaped columella, as seen in this scanning electron micrograph. These longitudinal openings result in a structure that resembles a lantern, thereby earning theses mosses the nickname of “lantern mosses”.
The spores germinate endosporically, which means that the spore cell divides within the cell wall, creating a multicellular structure prior to the development of the protonema.
The protonema is branched and multiseriate in Andreaeopsida.