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the whole groupe of Leucophanece. The structure of the cells 

 of Sphagnum, Dicranum glaucum, and Octoblepharum albidum, 

 has been pointed out by Mohl. Holes are said to occur in 

 Lidymodon sphagnoides, Ocloblepharum cylindricum, and in 

 Leucobryum minus, albidum and longifolium. Indeed, all the 

 Mosses called Leucophanece are distinguished like Sphagnum, 

 by peculiarities in the structure of the leaf, which consists of 

 two different species of cells — some narrow, and filled with 

 chlorophyll, others wider, transparent, and perforated with 

 pores. 



The epidermis, from extreme delicacy, is generally insepara- 

 ble from the body of the leaf ; but in a few of the more fleshy 

 leaved mosses its separation can occasionally be accomplished. 

 A preparation from the leaf of the Polytrichuin commune 

 agrees in all essential characters with the Phanerogamia : the 

 leaf is composed of an upper and lower cuticle, the inter - 

 veniug space being filled with cells of colouring matter or 

 chlorophyll. 



An opinion of the absence of stomata from this family 

 having universally prevailed amongst botanists, it was reserved 

 for Mr. Valentine to make the discovery of their existence. 

 It was in Bryum crudum that Mr. Valentine first detected 

 stomata; and on a subsecment examination of 103 British 

 Mosses, 78 were found to possess those organs. Their situa- 

 tion is very remarkable, being confined, with one exception, to 

 the theca. The thinness of the tissue will readily account for 

 their absence from other parts. In Bryum crudum they occur 

 only on the apophysis ; and wherever that organ is present 

 they are to be met with. On the apophysis of several species 

 of Splachnuni they exist in considerable abundance ; but in 

 S. ampullaceum they are confined to the upper part of that 

 organ, that being the only spot where the subcutaneous tissue 

 has separated from the cuticle. According to the age of the 

 theca their number and size vary : in the very young theca 

 they are very small, and much less numerous than in the 



