. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. CH. VI. THE BRYALES 189 as a papilla which grows out into a filament; or the endospore sometimes grows out in two directions, and one of the papillae remains nearly destitute of chlorophyll and forms the first rhi- zoid. The growth of the protonemal filaments is strictly apical, no intercalary divisions taking place except those by which lateral branches arise. If abundant moisture is present, the protonema grows with great rapidity and may form a dense branching alga-like growth of considerab
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. CH. VI. THE BRYALES 189 as a papilla which grows out into a filament; or the endospore sometimes grows out in two directions, and one of the papillae remains nearly destitute of chlorophyll and forms the first rhi- zoid. The growth of the protonemal filaments is strictly apical, no intercalary divisions taking place except those by which lateral branches arise. If abundant moisture is present, the protonema grows with great rapidity and may form a dense branching alga-like growth of considerable extent. Sooner or later vipon this arise the leafy gametophores. The develop- ment of the latter, as we have seen, also takes place abundantly. Fig. 97.âFunaria hyerometrica. A, Fragment of a protonemal branch with a young gametophoric bud; r, rhizoid; B, median optical section of the bud; C, older budâ I, surface view; 2, optical section; ;*â , apical cell; D, protonema with a still older gametophore (gam) attached. A-C, X225; D, X36. from the secondary protonemal filaments which may be made to grow from almost any part of the gametophore. The development of the bud is as follows. From a cell of the protonema a protuberance grows out near the upper end. This is at first not distinguishable from a young protonemal branch, but it very soon becomes somewhat pear-shaped, and instead of elongating and dividing simply by transverse walls, the division walls intersect so as to transform it into a cell 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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