. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. EQUISETINEJE 475- layer by the absorption of the others, but the remains of a sec- ond layer can be made out in stained sections of the ripe sporan- gium (Fig. 280, E). The vascular bundles of the sporophyll divide, one branch running to each sporangium. Of the two species studied by Bower, E. arvense and E. li- mosum, the latter showed more slender and strongly projecting sporangia, but otherwise they were alike. E. telniateia has even more massive sporangia than B. arvense. The sporophylls.
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. EQUISETINEJE 475- layer by the absorption of the others, but the remains of a sec- ond layer can be made out in stained sections of the ripe sporan- gium (Fig. 280, E). The vascular bundles of the sporophyll divide, one branch running to each sporangium. Of the two species studied by Bower, E. arvense and E. li- mosum, the latter showed more slender and strongly projecting sporangia, but otherwise they were alike. E. telniateia has even more massive sporangia than B. arvense. The sporophylls. Fig. 278.—Longitudinal section of an older sporangium, X260. The nuclei are shown in the archesporial cells. form a regular cone at the apex of the fertile branch, and are arranged in regular whorls, which vary in number in propor- tion to the size of the cone. The top of the sporophyll is al- ways polygonal in outline, owing to the lateral pressure of its neighbours, and very often they are regularly hexagonal, but this bears no relation to the number of sporangia, which usually exceed in number the angles of the sporophyll. Development of the Spores The development of the spores in Equisetum, while agree- ing in many respects with that of the eusporangiate Ferns, shows some peculiarities that are noteworthy, and as this offers one of the best cases for studying spore-formation, it was somewhat. 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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