MUSCI 145 



While the greater part of the internal tissue is used up in the formation 

 of the spores, the axial portion always remains unchanged in the form 

 of a solid columel. There are no elaters. Leitgeb regards the sporogone 

 of all mosses (including Sphagnaceae) as consisting, in its earliest stage 

 of development, of an inner mass of cells, the etidothedvm, distinctly 

 separated from the peripheral mass, or amphithedum. In Sphagnaceae 

 the archespore is formed from the latter, in the other orders from the 

 former portion. Among the typical mosses he again distinguishes three 

 types, viz. : (i) The Archidium-\.ypQ\ the spore-forming and sterile cells 

 are intermingled in the endothecium ; the spore-sac is separated from the 

 wall of the capsule by a bell-shaped cavity ; (2) the Andretza-type : the 

 endothecium is differentiated into the archespore and the columel, which 

 does not penetrate the former ; the innermost layer of the amphithecium 

 becomes the spore-sac, which is not separated from the wall of the 

 capsule by any cavity ; (3) the J?ryum-type : the endothecium is differ- 

 entiated as in the last case, but the columel penetrates the spore-sac, 

 which is separated from the wall of the capsule by a cylindrical cavity. 

 In all true mosses the sporogone is developed by means of a two-edged 

 apical cell. The ripe spores are roundish or cubical, with a thin, finely 

 granulated yellowish, brownish, or purple cuticularised exospore, and an 

 endospore of cellulose, and contain protoplasm, chlorophyll, and oil. 

 The number of spores in a capsule varies from sixteen (Archidium, Brid.) 

 to an immense quantity, and their size also varies inversely. Several 

 cases of hybridism have been recorded in mosses. 



Mosses are found in all climates, from the coldest to the hottest ; 

 they are most abundant in temperate regions and in damp situations, 

 clothing old walls, the trunks of trees, c. A few grow T in stagnant, and 

 one genus (Fontinalis, L.) in running water. Some species are sapro- 

 phytes. They are of scarcely any economical value, but are of great 

 importance in nature in the formation of soil. 



LITERATURE. 



Bruch & Schimper Bryologia Europrea, 1836-1865. 

 Schimper Recherches anatom. et physiol. sur les Mousses, 1848. 

 Wilson Bryologia Britannica, 1855. 



Hofmeister Pringsheim's Jahrb. wiss. Bot., 1863, p. 259. 

 Unger Sitzber. Akad. Wiss. Wien, xliii., 1861, p. 497. 

 Lorentz Moosstudien, 1864; Pringsheim's Jahrb. wiss. Bot., 1867, p. 363 ; Flora, 



1867. 



Berkeley Handbook of British Mosses, 1863. 

 Leitgeb Sitzber. Akad. Wiss. Wien, 1868, 1869. 

 Nageli Pflanzenphys, Untersuch., Heft i. p. 75. 

 Janczewski (Archegonium) Bot. Zeit, 1872, pp. 377 et seq. 

 Stahl Bot. Zeit., 1876, p. 689. 

 Kienitz-Gerloff (Sporange) Bot. Zeit., 1878, pp. 33 and 49. 



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