INTRODUCTION. 
Calyptra germen tegens, apice ad capsulam emittendam verticaliter rumpens, styligera. 
Capsula pedunculata, ovata vel sphasrica, in valvas quatuor, plus minusve longas, 
longitudinaliter fissa ; rarissime enormiter disrupta. 
Columella nulla. 
Semina filis spiralibus elasticis immixta. 
Char. Essentialis. Receptaculum fructus commune nullum. Perianthium monophyllum, 
tubulosum. Capsula pedunculo calyce longiori insidens, quadrivalvis. 
This distinguishes it at once from Marchantia, by the absence of the common 
receptacle for the fructification : from Anthoceros, by the four-valved capsule, and the 
want of a columella : from Targionia, by the monophyllous calyx : and from Riccia and 
Spharocarpus, by the long footstalks of the capsules. Indeed, were it not for the 
anomalous capsule of J pusilla, the Linnaean character, “ capsula quadrivalvis," would, I 
think, be admirably characteristic of the whole genus. 
I shall now offer an Analytical Table of the species described in the present work, 
arranged, in some degree, according to a method employed by Lamarck and De Candolle 
in their Flore Frarifaise, with alterations principally suggested by my valued friend, 
Mr. Lyell ; and I shall then proceed to give full and amended characters of them, with 
additional notes and synonyms, which will conclude this Introduction, already, perhaps, 
carried to too great a length. 
