Div. 2. ARTHRODONTEI. 



Teeth of peristome transversely jointed, composed externally of 

 two rows of coloured cells, with a divisural line between ; sometimes 

 wanting. 



t GAMOPHYLLE^. 



Leaves bifarious, inserted vertically, with a stipular appendage 

 adnate to the nerve and part of upper lamina and sheathing the stem. 



Fam. 5. FISSIDENTACE^. 



Plants gregarious or densely casspitose, very variable in size, simple 

 or branched, complanate, frondiform, acrocarpous or cladocarpous. 

 Leaves distichous, alternate, inserted vertically, each with a median 

 nerve, united to which for a greater or less extent is a second series 

 of small lobules or stipules, which with the upper half of the leaf base 

 sheathe the stem in an equitant manner ; cells parenchymatous, usually 

 incrassate, often strongly papillose. Capsule and peristome dicranoid. 

 Male infl. gemmiform, axillar, radical or terminal. 



Besides the great genus Fissidens, — of which Conomitrium and Ododicevas 

 are regarded as sections — the monotypic Sorapilla Spruce is the only other 

 member, though Lindberg also adds to the family his genus Mittenia 

 { = Mniopsis Mitt, non Dumort.) The species are distributed through all 

 the tropical and temperate regions of the world, and inhabit wet banks and 

 rocks, sometimes trunks of trees, and a few float in water. 



FISSIDENS Hedwig. 



Capsule on a terminal or lateral seta, symmetric or obliquely in- 

 curved, narrowed at base. Calyptra cucullate or mitriform. Peristome 

 of 16 teeth, cleft half-way or more into two rough subulate legs ; or 

 sometimes truncate and irregular, geniculate — inflexed when dry. Leaves 

 scalpelliform, the upper basal part conduplicate and amplexicaul. 



This most natural and extensive genus was established by Hedwig in 

 his Fund. Muse. P. II, p. 91 (1782), with the character " Peristome simple, of i(s 

 rather short inflexed teeth ; male fl. gemmiform, in the axils of leaves," and he refers 

 to it as species. Hyp. hryoides, taxifoUum, adiantoides and sciuroides L. figuring the 

 last, presumably as the type. For this reason, and too rigidly we think, 

 Lindberg retains Fissidens for Leucodon, and transfers all the rest to Schisto- 

 phyllum. By this latter name we are at once reminded of the very anomalous 

 structure of the leaves, and of the different theories which have been ad- 



