202 TORTULACE/E. 



It is curious that all three species seem to have their head- 

 quarters in Britain, and two of them have not been found else- 

 where. 



/Leaves tipped with clusters of gemmae /. getmnascens 



\ Leaves not tipped with gemmae 2 



/Leaves not bordered, nerve vanishing 3. flexifolium 



\ Leaves with pale border, nerve excurrent .3. recuruifolium 



1. Leptodontium gemmascens Braithw. (Didymodon 



gemmascens Mitt. ; Did. flexifolius var. gemmiferus Schp., 



Syn.) (Tab. XXX. D.). 



Loosely tufted, 1-2 inches high, bright green ; stems fragile, 

 scarcely branched. Leaves oblong-lanceolate or lanceolate- 

 acuminate, tapering, erecto-patent or spreading, not recurved, 

 rather crisped when dry, margin plane or erect, slightly sinuose 

 or undulated, finely spinulose-dentate at apex ; nerve reaching 

 apex, in the upper leaves excurrent and tipped with a bunch of 

 green, obovate gemmae; basal cells rectangular, the upper 

 irregularly hexagonal, obscure and opaque ; a single marginal 

 row somewhat more pellucid. 



Hab. Old thatched roofs, very rarely on trees ; Sussex ; near Dundee. Fruit 

 unknown. 



Originally considered a variety of the next species, but quite distinct in the form 

 and direction of the leaves. The gemmae are by no means confined to the tip of the 

 leaf, but may be found, often abundantly, in the axils of the upper leaves. Mr. 

 Mitten says that it is usually found on thatch that is just beginning to go, not on very 

 old and decayed thatch. 



2. Leptodontium flexifolium Hpe. (firyum flexifolium Dicks.; 



Didymodon flexifolius Hook, and Tayl., Schp. Syn.) 



(Tab. XXX. E.). 



In wide patches, 1-2 inches high, bright or yellowish green ; 

 stems slender, rather flexuose, fragile. Leaves distant, the comal 

 larger, erecto-patent or spreading and squar rose-recurved, 

 small (yi-^/l line in length), concave-carinate, rounded and 

 flexuose ; when dry erect and crisped ; shortly oblong-Ungulate, 

 apiculate at apex or shortly pointed ; margin recurved at base ; 

 in upper third strongly, irregularly spinose-denticulate ; nerve 

 narrow, yellowish, vanishing below the apex ; cells at base 

 shortly rectangular, above rounded-hexagonal, chlorophyllose, 

 incrassate, papillose on both sides ; a single row at margin 

 pellucid, crested with distinct single papillae on the edge. 



