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liRAlTHAVAlTE ; THE STUDV OF MOSSES. 



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reddish dusl, which, under the microscope, are seen to be sub- 

 globose and smooth, or rough with httle tubercles, consisting of 



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a cell filled with plasma and nuclei, enclosed in an outer skin or 

 exospore. You know that seeds of flowering plants germinate 

 only at one point^the embryo^but the spore does so at any 

 part, the skin bursts, and the contents project like a short tube, 

 w^hich, by continuous branching forms a felted layer of trans- 

 versely septate green threads, termed protonema, often seen in 

 winter as a film coating the soil on wet banks ; from the lower 

 cells of this, by lateral budding, the young moss-plants are 

 produced, from which roots, having oblique septa, proceed 

 downwards, and fix them to the substratum, and except in a few 

 minute species, the protonema then dies away. 



The stem now elongates, and lateral cells develop into 

 leaves ; and if we make a transverse section of the stem, we see 

 it has a central pith of long thin cells, external to which the 

 tissue is intermixed with solid or stereid cells, and enclosing all, 

 a thin cylinder of woody cells, which often bear a dense coat 

 of radicles by which the stems are matted together, and 

 moisture is retained. Few mosses have simple stems, but inno- 

 vations or annual shoots start off below the crow^n and continue 

 the growth, and occasionally subterranean stolons are thrown 



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out at the root as in Mniuni uudulaticin and Cliniaciuin. Stems 

 are usually erect or creeping, but sometimes they are pendent 

 when growing on trees, or submersed when attached to stones 

 under water. 



The leaves are never divided into lobes, and are commonly 

 ovate or lanceojate, but they may be nanowed to an awl-shape, 



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