481 



GENERAL NOTES ON MUSCI. 



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Dicranum latifolia. — Hook. Rather a Didymodon, the teeth are not 

 disposed in pairs, are binarily compound, and generally entirely coherent, 

 they are hispidate and semiopaque, occasionally they are ternarily com- 

 posed, the third part being rudimentary. Bridels generic figure of Cy- 

 nodon must be wrong ; whenever teeth are perforated, it is owing to the 

 adhesion of the component parts not being perfect, nothing appears to be 

 more difficult than to distinguish Dicranum, Didymodon, and Trichos- 

 tomum. Hooker represents the teeth of this species as bifid, they evident- 

 ly spring from the inner membrane, the columella is slightly contracted 

 and apiculate. It can scarcely be Bridels plant, he says the capsule is 

 cernuous and the opercule obtuse papillate. The margins of the leaves 

 are subincrassata. 



Did. capillaceus. — A true Didymodon, teeth rather obscurely ap- 

 proximated in pairs, from the inner peristome, sometimes united through- 

 out their length, generally partially united below the middle. Bridel says 

 they are not perforate ! his figure in the supplement is bad, he says high- 

 ly magnified, if so, it is not at all like the reality. 



Didymodon inclinatus. — The teeth of the peristome are often ternarily 

 composed, in this case they have of course two longitudinal lines, the per- 

 forations arise from the cohesion only taking place here and there, they 

 are distinctly approximate in pains, and I think that generally the ten- 

 dency to ternary composition only affects one tooth of each pair. I am 

 satisfied there is no limit between Didymodon and Trichostomum. 



Dicranum sollianum. — A true Dicranum. Teeth binarily composed, 

 but the longitudinal as well as the transverse lines, at least in the joined 

 portion, are very faint. These latter are not to be mistaken for the ra- 

 ther conspicuous trabecular. The composing cells are striate. 



Grimmia ovata. — Is certainly a Grimia, and not a Dicranum, or Cam- 

 pylopus. Teeth as in other Grimmiae so opaque, that the line of compo- 

 sition is scarcely discernible. 



In this, the peristome evidently originatis from the inner membrane of 

 the theca, which adheres to the outer only towards the mouth of the 

 capsule. The teeth of the peristome are binarily connate : they are 

 whitish and at least when dried punctulute : perforated here and there, or 

 entirely connate obtuse with emarginate apices, they cohere mutually to- 

 wards their bases. Sporules opaque unequal. I think it is doubtful whe- 

 ther Weissia should not be restricted to those species in which the teeth 



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