MOSSES. 



CLASS V. 



MOSS ESI. 



The spore produces a conferva-like thallus, the Pro-embryo or Protonema, from 

 which the leaf-bearing ]\Ioss arises by lateral branching and differentiation into 

 stem and leaf. On this plant the sexual organs are formed ; from the fertilised 

 oosphere proceeds the sporogonium, in which the spores are formed from a small 

 portion of die inner tissue. 



(i) T/ie Proionejna arises, in the typical Mosses, as a tubular bulging of the 

 endospore, which elongates indefinitely by apical growth and becomes septate. 

 The cells do not undergo any intercalary divisions, but form branches imme- 

 diately behind the septa ; and these also become septate, and usually show a limited 

 apical growth ; they may, in turn, produce ramifications of a higher order. The 

 part of the endospore which lies opposite the germinating filament may de- 

 velope into a hyaline rhizoid, which penetrates into the ground. The cell-walls 

 of the protonema-filaments are at first colourless, but as the primary axes lie upon 

 the ground or even penetrate into it, their cell-walls assume a brown colour, while 

 the septa, previously at right angles to the axis of growth, become oblique, and 

 assume posidons inclined in diff"erent directions (Fig. 226, B, h). The cells above 

 ground develope abundance of chlorophyll-grains ; and the protonema is hence 

 nourished independently by assimiladon, and not only attains a considerable size 

 in some genera, covering a surface of from one to several square inches like turf 

 with its densely matted filaments, but its term of life is sometimes, as it were, 

 unlimited. In most Mosses it altogether disappears after it has produced the leafy 

 stems as lateral buds; but where these latter remain very small and have only a 



^ W. P. Schimper, Recherches anat. et physiol. sur les Mousses (Strasburg 1848). — Lantzius- 

 Beninga, Beitnige zur Keiitniss des Baues der ausgewachsenen Mooskapsel, insbesondere des Peri- 

 stoms (with beautiful illustrations) in Nova Acta Acad. Leopold. 1847. — Hofmeister, Vergleich. 

 Untersuch. 1851. [On the Germination, Development, and Fructification of the Higher Cryptogamia, 

 Ray Soc. 1862.]— Hofmeister, in Berichte der Kon. Sachs. Gesellsch. der Wissens. 1S54.— Ditto, 

 Entwickelung des Stengels der beblitterten Muscineen (Jahrb. fur wissens. Bot. vol. III).— Unger, 

 Ueber den anat. Bau des Moosstammes (Sitzungsber. der Kais. Akad. der Wissens. Vienna, vol. 

 XLHI. p. 497).— Karl Miiller, Deutschlands Moose (Halle 1853).— Lorentz, Moosstudien (Leipzig 

 1864). — Ditto, Grundlinien zu einer Vergleich. Anat. der Laubmoose (Jahrb. fiir wissen. Bot. vol. VI, 

 and Flora 1867). — Leitgeb, Wachsthum des St.'immchens von Fo7Uinalis antipyretica u. von Sphagnum; 

 sowie Entwickelung der Antheridien derselben (in Sitzungsber. der Kais. Akad. der Wissens. Vienna 

 1868 and 1869).— Nageli, Pflanzenphysiol. Untersuchungen, Heft I, p. 15.— Julius Kiihn, Entwickel- 

 ungsgeschichte der Andreaeaceen (Leipzig 1870), (Mittheilungen aus dem Gesammtgebiet der Botanik 

 von Schenk u. Luerssen, vol. I). 



