THE GENERA OF MOSSES. 
133 
circular lines independent of, and sometimes intersecting 
the transverse ones, and chiefly situated at the extremities 
of the long cellules. 
The perichjetial leaves differ considerably in these plants 
from the cauline ones, and at an early period totally enve- 
lope the theca, scarcely bursting before it has attained its 
full size. At this time, especially in a dry state, they are 
remarkably scariose ; and from being, as it were, so glued 
together, as to prevent the form of each being visible, the 
whole bears no small resemblance to the calyx of some of 
the Jungermanm<2. 
Obs. The species or varieties of this genus are easily 
distinguished from those of all the other known genera. 
Their nearest artificial affinity is to Androea, from which 
they are at first sight separated by the entire theca, deci- 
duous operculum, and apparently pedunculated receptacle ; 
which last, combined with the absence of a seta, affords a 
distinctive mark from another series of allies, the Gymno- 
stomoidea. We have, under Jndraa, mentioned our rea- 
sons for considering the theca sessile : the same apply also 
to the present genus. We allude to the difference between 
the apparent peduncle and all true setae ; and for the close 
followers of Hedwig, to the situation of the pistilla, which 
are here formed immediately beside the theca, on the sum- 
mit of what we term the receptacle. But there is another 
circumstance, which, although we omitted to state under 
Andraa, applies no less to it, than to the genus under con- 
sideration. Hedwig, among his definitions, describes va- 
ginula — Membrana tenuissima, pedunculi basin in^vol- 
vens prima cetate calyptra continua f yet we find him de- 
scribing both Andraa and Sphagnum as possessing setae. 
But it ought to be remarked, that Hedwig, in consequence 
of his liypothesis of the constant presence of a true seta, was 
