It has been in some sort an advantage to Hepaticology and Liclien- 

 ology to have had the species united for a long period under a single 

 generic name, for it has conduced to greater wealth and variety of spe- 

 cific names. When a young botanist, it had seemed to me desirable to 

 avoid duplicate specific names in the same natural order, and on 

 mentioning this to Taylor and Montagne I was pleased to find that, as 

 far as possible, it was their own rule of practice. Some of Taylor's 

 names are, indeed, very original and expressive, although it may be 

 admitted that in his eagerness to found new species he sometimes 

 attached too great an importance to the differences he had so acute an 

 eye for detecting. 



This brings me to the subject of synonyms, of which I may say I 

 have quoted as few as possible — no more, in fact, than were needed to 

 authenticate a name and to guid© the student to original descriptions of 

 a genus or species. For synonymy belongs more to history than to 

 science, and has now assumed such vast proportions as to demand a 

 separate treatise for its adequate elucidation, Exsiccata of Cephalozics 

 can rarely be cited with any confidence, the specimens being too often 

 incorrectly named, and those given under the same number and name 

 being sometimes not all of one species in the different sets. In illustra- 

 tion of this, let the reader consult my remarks under C. catenulata. 



In the descriptions I have generally alotted more spaceto the European 

 species. The South American species are all described at length in my 

 forthcoming "Hepaticse of the Amazon and Andes", so that I have here 

 mostly limited myself to a brief specific character of each. In the 

 terminology I have adopted the term foliola for the underleaves, or 

 stipules — the so-called amphigastria of authors ; and I call the upper 

 face of a stem or branch, antical ; the under or rooting face, postical ; 

 and the sides, right and left of the axis, lateral. In estimating the 

 comparative dimensions of leaf-cells I have used the scale proposed in my 

 paper on Anomoclada (Journ. Bot. 1876J which I here subjoin for refer- 

 ence*. As to the position of the inflorescence I have called it clado- 



*The comparative size of the cells of Hepaticse : — 



Cellule diametro 



magna (large) i/io mm = -lo mm 



majusculcB (rather large) 1/20 mm = '05 mm 



mediocres (medium size) 1/30 mm = '033 mm 



parvulee (smallish) 1/40 mm = -025 mm 



parvse (small) 1/50 mm = -02 mm 



minutulse (very small) 1/60 mm = '0167 mm 



minutse (minute) 1/70 mm = -0143 mm 



minutissimsB (very minute) 1/80— i/ioo mm = •0125— "oi mm. 



