The Irish Naturalist. 
June, 
As the lyyons mills have now ceased to be a means of intro- 
ducing aliens into the country, it is worth noting that in the 
Douglas Herbarium there are quite a number of foreign plants, 
some twenty of which are from the neighbourhood of Straffan 
and I^yons, and it is possible that some of these may have 
been brought in with the grain coming to these mills. 
I have to thank Mr. N. Colgan, Mr. E. G. Baker, Mr. R. U. 
Praeger, and the Keeper of the Kew Herbarium for help in 
naming some of the plants in the above lists. 
Dublin Museum. 
REVIEW. 
BEITISH AND IRISH LIVERWORTS. 
A Revised Key to the Hepatlcs of the British Islands. By 
Symers M. Macvicar. pp. 20. Eastbourne: V. T. Sum field, 1906. 
Price 9^/. 
This useful work, a first edition of which was issued in 1901, appears now 
iu an improved form. It has been completely revised, many new British 
species added, the arrangement in the " Moss Exchange Club Census 
Catalogue of British Hepatics" followed, and so many alterations and 
improvements made that we advise everyone interested to obtain a copy. 
The study of I^iverworts is difficult for a beginner. This Key is intended 
to help him to make out the species. It is an aid to the use of a larger 
work. There is first a dichotomous key to the genera, and a new feature 
iu the present edition is the use made of the underleaves for diagnostic 
purposes. 
This is followed by a similar Key to the species. Plain and naked-eye 
characters, as opposed to microscopic, have as far as possible been used, 
avoiding those drawn from perianth, inflorescence, or cell-structure. 
In its previous form this Key was found most helpful, not only by 
beginners but more advanced students The value of the new edition 
can only be properly tested by use, but we believe it will be found an in- 
valuable aid to the use of Lett's or Pearson's larger works on this group. 
We notice that many small alterations, suggested no doubt by experience, 
have been made in the salient characters given for each species. 
There is a short introduction, in which some practical hints are to be 
found for the examination of these plants. So much variation prevails 
even in the same plant, we are advised to examine several stems and 
several leaves, and take the average as our type. 
C. H. Waddei.i<. 
