tftie , même d'après ces principes si clairs eri 

 apparence au premier aspect , il sera difficile 



double , the narrower teeth or cilfa arising front an 

 internai membrane; whereas in most of the other species 

 ivich hâve ciliary processes they originale on the sidô 

 of the larger teeth. In Dicrauum the teeth are subject 

 to vary , and to border on the one h and, itpon Trichosto- 

 inuai , and on the other vpon Griramia , in ■wich genus 

 xve find the teeth sometimes split. In Léskea it is dijjicult 

 sometimes to see the inner membrane rising aboyé thè 

 mouth of the capsule , and then the peristome precisely 

 agrées with that o/"Neckera , to wich perhaps the genus 

 ought to be united. In those Masses wich màke yearly 

 shoots , thèse sometimes arise so near the point of insertion 

 of the fructification as to tnake the fruit-stalh appear 

 latéral , wich is specially the case in the genus Bartramia. 

 Even the caljptra of s orne Mossês seems to be interms- 

 diate , hai'ing so slight a fissure , that wè are doubtful 

 ■wich we should call that ofC'mcYidotus- and o/"S t> I a chn uni. 

 Sometimes in Tricliostomum , besides the short fissure at 

 the base , we see in T. microcarpon a single longitudinal 

 cleft reaching three-fourths of the way up , making it 

 appear a truly dimidiate caly ptra. Such too is the case with 

 the T. funale of Schw,egp.iciietv wich gave him occasion 

 to say of it : j> Calyplrse forma ab affiniluis Tnchostomis 

 etiara recedit „ et rursùs caljptram ad définition es genericas 

 adliibendam non esse demonstrat «. I/i this , and indeed 

 in ail the previously mealionccl cases , the question is 

 to be decided by the habit of the plant , wich thus has 

 its share of influence in the formation of gênera «. 



IIooker and Taylor , Muscologia britannica. Introd, 

 p. r et ri. 



Il 



