190 The Irish Nattoalist. August, 



t 



REVIEWS. 



IRISH PLANT DISTRIBUTION, 



On Types of Distribution In the Irish Flora, By R. IvI,oyd 

 PraEGER, B.A., B.E. — Proc, Roy. Irish Acad., Vol. xxiv., 1902. 



Irish plant distribution already possesses a considerable literature of 

 its own, but, perhaps, nowhere will the student find a more interesting 

 resutne of the subject than is set before him in this paper of sixty pages. 

 Its most obvious merit, one which even the veriest skimmer cannot fail 

 to recognise, is the skilful use which the writer has made of the graphic 

 method of exhibiting complex groups of facts. No less than sixty-two 

 charts serve to visualize for the reader the various generalizations which 

 may be drawn from the large mass of material made available of late 

 years in the second edition of Cybele Hibernica and in the author's own Irish 

 Topographical Botany. The chart on page 8 showing the distribution in 

 Ireland of the Scottish type plants, the other on page 11 dealing with 

 the Highland type, and those on pages 19 and 20 dealing with the cal- 

 cicole and calcifuge groups, may be taken as examples of the great 

 advantage which the graphic method has over unaided letterpress. 



The paper is divided into two fairly equal sections. The first is con- 

 cerned mainly with the relations of the Irish to the British flora, and 

 exhibits in an excellent set of charts the distribution in Ireland of 

 Watson's well-known types. In this section, too, are some well thought 

 out paragraphs on the calcicole and calcifuge groups, a series of charts 

 vShowing the distribution of mountain land in Ireland, and some discus- 

 sion of such abstruse questions as the probable cause of Ireland's poverty 

 in Germanic species, or the anomalies in the distribution of her High- 

 land type plants. On the whole, however, there is little in this first 

 section, interesting as it is, to call for special comment. A passage on 

 page 22 may be noted as an example of the critical operation known as 

 breaking a butterfly on the wheel. The butterfi}' in this instance is a 

 simile used in the Introduction to the Second Edition of Cybele Hibernica^ 

 where the plant migration which gave to the British Isles at the close 

 of the last glacial epoch the bulk of their present flora, is likened to an 

 army with advance-guard and rear-guard. It is the vice of all similes 

 that they limp when urged too far, and the plant-army simile is no better 

 in this respect than any other. But it presents, at all events, a picture 

 to the mind's eye; and this first duty of a simile the plant- empire 

 simile, which Mr. Praeger proposes as a substitute, is unable to dis- 

 charge. There is a curious oversight in this same passage, where Mr. 

 Praeger speaks of the plant-army having to overcome a "presumably 

 weaker flora which was in possession of the ground," the fact being that 

 the ground in question at the close of the glacial epoch was quite naked, 

 a veritable tabula rasa from the botanical point of view. There appears 



