422 West. — Structure, &c., of Secretory Tissues of Marattiaceae. 
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t. xii, 1898. 
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math.-naturw. Kl. d. kais. Akad. d. Wiss., Bd. lxxviii. Wien, 1905. 
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EXPLANATION OF PLATE XVIII. 
Illustrating Mr. West’s paper on the Structure and Development of the Secretory 
Tissues of the Marattiaceae. 
Figs. 1, 2, and 3. Successive stages in the development of mucilage-canals. In Fig. 3 the 
transitory epithelium is shown. From longitudinal sections of a young petiole of Angiopteris evecta , 
Hoffm. x 280. 
Fig. 4. Part of a transverse section of an older petiole of Angiopteris evecta , Hoffm., showing 
four adult mucilage-canals in transverse section. Note complete absence of epithelial cells, t.c. = 
tannin cells, x 100. 
Fig. 5. Part of a longitudinal section of a young petiole of Angiopteris evecta , Hoffm., showing 
early stage in development of a mucilage-canal, t.c. = tannin cells, x 60. 
Fig. 6. Early stage in the development of a mucilage-canal. The protoplasm of many of the 
small cells is undergoing mucilaginous degeneration ; at a 1 the cell-walls have disappeared. From 
a transverse section of a young petiole of Danaea nodosa , Sm. x 280. 
Fig. 7. Part of a transverse section of an old root of Angiopteris evecta , Hoffm., showing early 
stage in the formation of a mucilage-canal by the mucilaginous degeneration of part of the cortical 
parenchyma, m. = mucilage, x 280. 
Fig. 8. Part of a longitudinal section through the apical region of a large root of Marattia 
Cooperi, Mre., showing a young mucilage-canal. Note absence of epithelial cells, m. = mucilage; 
n. — nuclei of disorganized cells floating in the mucilage, x 100. 
Fig. 9. Part of a transverse section of an adult petiole of Kaulfussia aesctdifolia , Bl., showing 
a large irregular mucilage-canal formed by the mucilaginous degeneration of typical parenchymatous 
cells of the ground-tissue, m.c. — mucilage-canal of the usual type, x 100. 
Fig. to. Early stage in the development of a mucilage-canal from a single row of canal-initials. 
From a longitudinal section through the apical region of a large root of Marattia Cooperi , Mre. 
x 100. 
Fig. 11. Part of a transverse section of a large root of Danaea alata , Sm., showing early stages 
in the development of mucilage-canals, t.c. = tannin-cell, x 100. 
Fig. 12. Early stage in the development of a mucilage-canal. The protoplasm of many of the 
small cells has undergone mucilaginous degeneration, while several of the cell-walls have already 
disappeared. From a transverse section of a young petiole of Marattia Cooperi , Mre. x 280. 
Fig. 13. Part of a longitudinal section through the apical region of a large root of Danaea 
nodosa , Sm., showing early stage in the development of a mucilage-canal, x 280. 
Fig. 14. Early stage in the development of a mucilage-canal. The protoplasm of several of 
the small cells has• undergone mucilaginous degeneration; at x the cell-walls have completely 
disappeared. From a longitudinal section of a young petiole of Kaulfussia aescidifolia , Bl. x 280. 
