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KEY TO THE GENERA. xli 



("Leaves 3-ranked ; stem long, usually floating So. Fontinalis 



*\ Leaves complanate 5 



/Branches pinnate ; leaves undulate (except complanata) 82. Neckera 



■* \ Branches not pinnate ; leaves flat (except undulatum) 113. Plagiothecium 



, /Leaves covered at back with long papillae 97. Pterigynandnim 



\ Leaves smooth (or with a few papillae near apex) 7 



/Ls. very concave, imbricate, with long filiform apiculus 103. Myurium 



' \ Ls. without filiform apiculus 8 



fLs. whitish, with cells in several layers 27. Leucobryum 



[_Ls. with cells in one layer only 9 



f Ls. obtuse, or widely and bluntly pointed, or aprculate 10 



"\Ls. acute or acuminate 12 



("Aquatic or marsh plant 115. Hypnum 



\Terrestrial plant 11 



/Stem and ls. pale; auricles of small, opaque cells 102. Cylindrothechim 



\ Either the stem red, or the auritles of large, thin cells 115. Hypnum 



("Stem and branches red, often with paraphyllia; plant robust ...116. Hylocomium 



\Stem and branches not red 13 



/Leaves very minute ; plant slender, conferva-like 114. Amblystegium 



•*\ Leaves easily visible 14 



{Leaves wide-ovate, sharply serrate, with short acumen in. Hyocomium 

 Leaves entire, or with a long, finely serrulate acumen 15 



/Ls. more or less squarrose or recurved 115. Hypnum 



-*\Ls. imbricate (and plicate) or sub-secund 16 



, /Acumen serrulate 113. Plagiothecium 



\ Acumen entire 17 



/Ls. reddish, more or less plicate, at least when dry iqj. Orthothecium 



'\Ls. not reddish nor plicate 18 



o/Ls. ovate below ; capsule erect, lid conic 104. Pylaisia 



\Ls. lanceolate ; capsule cernuous, or erect with rostrate lid iij. Hypnum 



R. Plant with gemmae or filaments on the leaves op on 

 special receptacles. 



/Plant with special stalked receptacles 2 



\ Plant without such receptacles 3 



{Gemmae in stalked roundish heads 6f. Aulacomnitim 

 Gemmae in terminal leafy cups 3. Tetr aphis 



{Gemmae collected at the end of the nerve 4 

 Gemmae or filaments on the surface of the leaf or nerve 5 



/Leaves entire 4g. Ulota 



^\ Leaves serrate 41. Leptodontium 



{Appendages confined to the (often dilated) nerve 30. Tortula 

 Appendages scattered over the face of the leaf .Jo. Orthotrichum 



S- Nerve wide, about one-third of bass of leaf. 



/Ls. with subulate points, mostly formed by the nerve 2 



1 \ Ls. lanceolate, nerve not reaching apex 02. Porotrichum 



/Ls. with coloured or dilated angular cells 3 



2 \ Ls. without special angular cells 5 



/Ls. suddenly narrowed above base to a long subula 4 



3\Ls. more gradually subulate 24. Campylopus 



{Basal auricles of ls. large and inflated 2J. Dicranodontiitm 

 Basal auricles slightly developed or absent 26. Dicranum 



{Ls. secund ; upper cells not much elongate .' 21. Dicranella 

 Ls. spreading ; upper cells very long and narrow 74. Leptobryum 



