Mosses and Lichens 



Name. The specific name albidum, white, refers to the 

 colour of the leaves. 



Plant (gametophyte) . Spongy, soft when wet, brittle and 

 white when dry. 



Leaves. Close, thick, composed, except on the borders, of 

 two or three superimposed layers of large porous cells without 

 leaf-green, these separated by a layer of simple, narrow cells 

 containing leaf-green. 



Veil (calyptrd). Large, split on one side. 



Spore-case. Erect. 



Pedicel (seta}. Short. 



Lid (operculum). Plane at the base with 

 an oblique and awl-shaped beak. 



Natural size. 



Spore-case with 

 eight teeth. 



Leaf. 



O. albidum. 



Teeth (peristome) . Eight, short, broadly lance-shaped, pale- 

 yellow and transparent. 



Spores. Mature in spring. 



Distribution. Common in the warmer parts of the world 

 except Europe. 



Genus CERATODON, Brid. 



The species of this genus are small erect plants growing in 

 bright or dark-green cushions on soil or in the crevices of rocks. 



The leaves are lance-shaped and keeled, with entire or toothed 

 margins, and a vein extending to or beyond the apex. 



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