428 baker's north YORKSHIRE. 
few of the tropical mosses are to be met ^vith in sheltered 
nooks of our Islands — outliers as they may be called — and 
are probably remnants of a tropical flora in the earlier 
g^eological periods of our Islands, and these are added to 
their nearest allies, in the best way, by the author ; and 
a compendium of this arrangement is given. 
There is, however, no finality in any natural arrangement 
of plants, and we can only hope that students of the future 
may keep improving the method of classifying these plants 
by additional and more accurate observations which future 
optical improvements may afford. 
Dr. Braithwaite's arrangement in "The British Moss 
Flora " is as follows : — 
MUSCI ACROCARPI. 
SECT. I.— SCHISTOCARPI. 
Fam. I. AxDRE.^iACE.ii:. 
Genus 1. Andpeaea Ehvhart. 4 species and some 
varieties. 
SECT. 2.— STEGOCARFJ. 
Fam. 2. BuxBAUMiACE.^:. 
(ienus 1. Buxbaumia Haller. 2 species only known of 
this in Britain. 
Fam. 3. Georgiace.^:. 
Genus i. Georgia Ehrhat-t. 2 species. 
Fam. 4. POLYTRICHACE.^. 
Genus i. Catharlnea E/irhart. 3 species. 
,, 2. Oligotrichum Lam. De C. i species. 
,, 3. Polytrichum Dill. 11 species and varieties. 
Fam. 5. FlSSIDENTACE.^i. 
Genus 1. Fissidens Hedimg. 17 species and var. 
Fam. 6. Leucobryace.^s. 
Genus 1. Leucobryum Hampe. i species. 
Fam. 7. DicRANACE.t. 
Genus i. Archidium Bridel. 1 species. 
