Maslova, E.V., Yu.V. Mosseichik, I.A. Ignatiev & M.S. Ignatov. Bulbosphagnum, a new form genus for vegetative propagules of the Palaeozoic order Protosphagnales
Arctoa (2016) 25: 314–331
Spheric to ovoid or bulb-like brood bodies are found in Upper Palaeozoic mosses of the order Protosphagnales. They developed on stems and leaf costae, and putatively also on the apical parts of leaves. Their surface was smooth or, more commonly, rough due to short rhizoid initials densely covering their surface all around. It seems that rhizoids developed especially after brood bodies started growth, becoming larger and then forming stem. Rhizoids on brood bodies and on stems growing out of them have oblique cell walls, characteristic to all other mosses. They definitely belong to species of Protosphagnales, wherefrom they were not reported earlier. However, as the taxonomy of the genera of protosphagnalean mosses is based primarily on leaf characters, a new form-genus Bulbosphagnum is described to accommodate numerous brood bodies themselves and also brood bodies with leafless stem bases. In the extant flora, the most similar brood bodies are known in Oedipodium where they also may form on various parts of plants and have similar shape and size, although differ in fewer rhizoid production as compared with Bulbosphagnum.