. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. VI. THE BRYALES cells, when the capsule is ripe, that effects the separation be- tween the operculum and theca. The peristome arises from the fifth layer of cells from the outside of the operculum. If a median longitudinal section of a nearly ripe capsule is examined, the row of cells belonging to this layer (Fig. iii, per), is at once seen to have the outer walls strongly thickened, and this thickening extends for a short distance along the transverse walls. The inner walls of the cells also
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. VI. THE BRYALES cells, when the capsule is ripe, that effects the separation be- tween the operculum and theca. The peristome arises from the fifth layer of cells from the outside of the operculum. If a median longitudinal section of a nearly ripe capsule is examined, the row of cells belonging to this layer (Fig. iii, per), is at once seen to have the outer walls strongly thickened, and this thickening extends for a short distance along the transverse walls. The inner walls of the cells also show a slight increase in thickness, but much less marked than the outer ones. A similar thickening of the cell walls occurs also in about three rows of cells which run from. s. "â â Fig. 112.âLongitudinal section of a fully-developed sporogonium of Funaria hygro- metrica, X about 40; s, seta; a, apophysis; sp, spores; col, columella; r, annulus; y, operculum. the outside of the capsule to the base of the peristome, and form the rim of the "theca" or urn. The epidermis of the whole capsule has its outer walls very much thickened, and upon the apophysis are found stomata quite similar to those found upon the sporogonium of Antho- ceros or upon the leaves of vascular plants. Haberlandt ((4), p. 464), showed that while the form of the fully-developed stoma in Funaria differs from that of most vascular plants, this difference is secondary, and that in its earlier stages no difference exists. This can be easily verified, and with little difficulty all the different stages found. The young stoma (Fig. 113), has the division wall extending its whole length,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Campbell, Douglas Houghton, 1859-1953. New York, The Macmillan Company;
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