33 
KEY TO THE GENERA AND SPECIES OF BRITISH 
MOSSES. 
By tue Rev. H. G. Jameson. 
(Puate 802.) 
Tue following key is not intended to _ the place of a more 
detailed text-book, but merely to serve as a clue by which the 
student may ascertain in what part of his ‘ik = should vi pe 
the description of any unknown specimen. ‘There is, I believ 
complete key published for British Mosses, and fie ‘existing ard 
such as Wilson’s, are founded almost entirely on distinctions of 
the fruit, aie leaving the student quite at a loss with regard to 
such com and easily distinguished Mosses as nig: tamar- 
iscinum, noe sep asi Mnium undulatum, &c., ill 
among the latter, however, are so unlikely to be gathered, except 
when in fruit, that they are neglected in the section which deals 
with barren plants. 
The key to the genera is so arranged that the first line after 
each asterisk forms a heading to the section belowit. The Key 
may therefore be gone through rapidly by reading these headings 
a 
ac. 
question, after which the reference-num must be followed until 
the name of the genus is found. It is well to remember, however, 
that the key — be begun at the beginning, or mistakes wi 
Phe ser €. Jey under the fifth asterisk, headed ‘* Leaves 
nerveless,”’ "doe not include Schistostega, pence had already been 
separated off in the preceding section. If the student can already 
recognise the Acrocarpous and Pleurocarpous Groups, he will find 
appears again lower down at No. 12. 
The prasciclacare Sreachoet is that of Hobkirk’s Synopsis, as 
ho tgs is likely to be in the hands of every student. Those who 
s Dr. Braithwaite’s British Moss Flora will have already his 
bs re the —— of which I have, with his kind permission, 
made frequen 
The owites plate is intended to assist beginners, who may 
be puzzled by terms to which they have not been accustomed, even 
in General Botany. It is presumed, however, that t the student will 
not attempt to distinguish individual Mosses without having studied 
Journat or Borany.—Vot. 29. ([Fesruary, 1891.] »D 
