Usage examples (9)

• The archesporium arises by the next divisions in the outer layer of cells, and thus extends over the summit of the columella.
• In the young condition the wall of the capsule, which consists of two layers of cells, encloses a mass of similar cells developed from the archesporium.
• In some species, although the columella and archesporium arise in the usual way, both give rise to mingled spores and elaters, and no sterile columella is developed.
• The development of the sporogonium proceeds as in the Bryales, but the dome-shaped archesporium extends over the summit of the columella and an air-space is wanting.