[6] The extremely reduced state of Buxbaumia plants raises the question of how it makes or obtains sufficient nutrition for survival.

[3] However, a recent study of the chloroplast genome in Buxbaumia[9] failed to find any reduction in selective pressure on photosynthetic genes, suggesting that they are fully functional in photosynthesis, and that the moss is not mycoheterotrophic.

Unlike most other mosses, the endostome (inner row) does not divide into teeth, but rather is a continuous pleated membrane around the capsule opening.

[3][12] Diphyscium shares with Buxbaumia one other oddity of the sporophyte; the foot (stalk base) ramifies as a result of outgrowths, so much so that they may be mistaken for rhizoids.

[8] The asymmetric sporophytes of Buxbaumia aphylla develop so that the opening is oriented towards the strongest source of light, usually towards the south.

[8] The species often grows together with the diminutive liverwort Cephaloziella, which forms a blackish crust that is easier to spot than Buxbaumia itself.

[21] However, recent phylogenetic studies based on genomic and transcriptomic data[22][23] clearly support it as the sister group of all other Bryopsida.