. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. EQUISETINEM 463 greater part remains but little changed. By this time, in E. telmateia, numbers of cells with peculiar contents are noticed scattered through the pith and cortex (Fig. 269). The con- tents of these are dense, and stain deeply, indicating the presence of mucilaginous matter, and probably tannin, their appearance and behaviour being very much like the tannin cells of Angiop- teris or Marat Ha. In the older parts of the section the nodal cells remain short, while the internodal ce
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. EQUISETINEM 463 greater part remains but little changed. By this time, in E. telmateia, numbers of cells with peculiar contents are noticed scattered through the pith and cortex (Fig. 269). The con- tents of these are dense, and stain deeply, indicating the presence of mucilaginous matter, and probably tannin, their appearance and behaviour being very much like the tannin cells of Angiop- teris or Marat Ha. In the older parts of the section the nodal cells remain short, while the internodal cells elongate very much and separate the nodes with their attached foliar sheaths. With this growth is associated the formation of the characteristic lacunae. In all. Fig. 269.—Longitudinal section of the young stem, showing the junction of the foliar and internodal bundles; tr, the primary tracheids; x, x, tannin-bearing cells. the large species the growth of the medullary cells very soon ceases to keep up with the expansion of the stem, and they are torn apart and almost completely disappear, leaving a great cen- tral cavity in each internode separated from the neighbouring ones by a thin diaphragm,—all that is left of the medulla in the fully-developed stem. The leaves of successive sheaths alter- nate, and a study of the course of the vascular bundles shows that at each node the alternating bundles of successive inter- nodes are connected by short branches. Corresponding 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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