124 TASMANIAN BRYOPHYTA, 



Yam. 5— MNIACEAE. 



Branches erect, simple or fascicled, from a creeping 

 radiculosie stolon. Leaves from delicate to rather firm, 

 lanceolate to oblong, the cells rotundo-quadrate, medium 

 sized, thin or slightly incrassate, rarely large rhomboid, 

 nerve from lost above to excurrent. Normally the fruit 

 is terminal, but in three of the Tasmanian genera it arises 

 low down on the branch, or beneath a fasciclei; seta long, 

 slender ; lid various ; calyptra cucullate ; peristome from 

 small, single, and irregular to perfect (that is of two 

 series), the exostomei of 16 strong, lanceolate teeth, the 

 endostome of 16 transparent processes. The family 

 is not a very natural one, but it would not further matters 

 to split it into many small, partially allied groups. Gonio- 

 bryum, with the habit of Rhizogonium, has almost the 

 tissue of a Bryum, and in both these the peristome is very 

 like that of Bryum. Mittenia is an aberrant genus, and 

 is sometimes placed in a family by itself, a proceeding war- 

 ranted by its peculiar peristome and leaf insertion. Some 

 bryologists have placed it in FLSsidenta,ceae, but beyond 

 superficial resemblance, there appears little to waiTant it. 



LEPTOSTOMUM : Leaves rather blunt, with a ter- 

 minal, long, dentate hair. Peristome an irregular 

 membrane. 



LEPTOTHECA : Leaves acute, with an excuiTent 

 nerve. Peristome double, but teeth very short 

 and slender. 



HYMENODON : Leaves small, oblong, in one plane, 

 with a terminal, long, simple hair. Peristome of 

 one series of thin, lanceolate teeth. 



RHIZOGONIUM : Leaves various. Peristome per- 

 fect. Outer series of bold, lanceolate teeth ; inner 

 of delicate, slender processes, 



GONIOBRYUM : Leave® translucent, cells large, 

 rhomboid. Peristome perfect. 



MITTENIA : Leaves in two rows ; vertically insert- 

 ed, dorsial margin decurrent. Peristome of two 

 series, the outer of very long, slender bristles, the 

 inner of 16 short, brown cilia^ 



