Fig. 1.

Different developmental stages of P. patens. (A) A 3-week-old colony showing protonema growth that consists of chloronemal cells in the center and caulonemal cells in the periphery. (B) Chloronemal filaments with a characteristic cross wall oriented perpendicular to the cell axis (arrows). (C) Caulonemal filaments with a characteristic cross wall oriented oblique to the cell axis (arrows). (D) A leafy shoot, the gametophore, build-up of a stem, leaf-like organs, the phyllids and root-like organs, the rhizoids. (E) Close-up of the top of a gametophore, carrying the gametangia: the female archegonia (f) and the male antherida (m) (arrows). (F) Close-up of the top of a gametophore carrying the sporophyte with a mature spore capsule.