In all other Bryales there is a definite columella extending from the base to the apex of the capsule, the archesporium is derived from the outermost layer of cells of the endothecium, and an air space is formed between the spore-sac and the wall. ❋ Various (N/A)
In _Sphagnum_, as in _Anthoceros_, the archesporium is derived from the amphithecium; in all other mosses it is the outermost layer of the endothecium. ❋ Various (N/A)
The lower tiers [v. 04 p. 0652] form the foot, while in the upper part the first divisions mark off the columella, around which the archesporium, derived from the amphithecium, extends. ❋ Various (N/A)
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. ❋ Various (N/A)
C, Median longitudinal section of a capsule, with the seta gradually widening into the apophysis at its base; d, operculum; p, peristome; a, annulus; c, columella; s, archesporium; h, air-space between the spore-sac and the wall of the capsule. ❋ Various (N/A)
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. ❋ Various (N/A)
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. ❋ Various (N/A)
In all cases (except _Archidium_) a columella is present, and all the cells derived from the archesporium produce spores, no elaters being formed. ❋ Various (N/A)
The archesporium arises by the next divisions in the outer layer of cells, and thus extends over the summit of the columella. ❋ Various (N/A)
The spores are derived from the endothecium, but no distinction of a sterile columella and an archesporium is established in this, a variable number of its cells becoming spore-mother-cells while the rest serve to nourish the spores. ❋ Various (N/A)
a strand of narrow elongated cells forming the columella, and between this and the wall spores mixed with elaters are formed from the dome-shaped archesporium, the origin of which has already been described (fig. 4, D). ❋ Various (N/A)
C, E, F) the embryo is formed of a number of tiers of cells, and the archesporium is defined by the first divisions parallel to the surface in the cells of one or more of the upper tiers; a number of tiers go to form the seta and foot, while the lowest segment (a) usually forms a small appendage of the latter. ❋ Various (N/A)
