. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. 524 MOSSES AND FERNS CHAP. sporangium of the strobilus. This is much larger than the microsporangia, and the sporophyll correspondingly large. In other species, e. g., S. apus, there may be several macrospo- rangia. According to Hieronymus the position of the stro- bilus conditions to some extent the development of macrospo- rangia, which are either basal, or in that part of the strobilus. Fig. 303.—Selaginella Kraussiana. Horizontal section of the apex of the stem, X77', B, the apical meriste
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. 524 MOSSES AND FERNS CHAP. sporangium of the strobilus. This is much larger than the microsporangia, and the sporophyll correspondingly large. In other species, e. g., S. apus, there may be several macrospo- rangia. According to Hieronymus the position of the stro- bilus conditions to some extent the development of macrospo- rangia, which are either basal, or in that part of the strobilus. Fig. 303.—Selaginella Kraussiana. Horizontal section of the apex of the stem, X77', B, the apical meristem of the same, X450; s, the apex of the main axis; s', a young lateral branch; B, B, young leaves; L, ligula of the leaf; C, D, longitudinal sec- tions of the base of older leaves, X450; i, i, lacuna surrounding the vascular bun- dles of the stem; f, one of the trabeculs. nearest the ground. Thus in dorsiventral strobili they are de- veloped on the ventral side; in pendent ones they may form at the apex of the strobilus. Miss Lyon made some interesting observations upon the development of the sporangia in S. apus and S. rupesfris. In the latter species the strobili begin to de-. 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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