340 



NA TURE 



{Feb. 



rence of their physiognomic features in many continental 

 areas, adds to tlie difficulties of plant geographers. ' He 

 shows that no order, no sub-order, not even a tribe, 

 is endemic in the smaller oceanic islands, and that the 

 very distinct genera that occur are not disproportionate. 

 To the question, Do the flowers of endemic insular plants 

 present any peculiarities of size, shape, or colour? we get 

 an instructive answer in the tabulated analysis of the 

 endemic plants of St. Helena. From it we learn that 

 "the size of the flowers and flower-heads in this flora is 

 on the whole rather above than below the average of those 

 of their allies in other parts of the world. When we come 

 to colour, however, the equality fails altogether, red being 

 almost entirely wanting in the insular plants, and blue 

 unknown." The absence of butterflies and the abund- 

 ance of moths on the island is a significant concomitant 

 circumstance, as Mr. Hemsley remarks. Particulars 

 are not yet forthcoming from other islands to permit 

 of like analysis, and Mr. Hemsley merely concludes that 

 brilliantly-coloured flowers are rare in such islands. 



Amongst the special features of insular floras discussed 

 and illustrated by Mr. Hemsley in the introductory 

 portion of the volume, is the preponderance of shrubby 

 and arboreous Composita;, and of woody plants generally. 

 That islands " often possess trees and bushes belonging 

 to orders which elsewhere include only herbaceous 

 species "as Darwin stated, he shows, by tabulated evi- 

 dence of the occurrence of arboreous or shrubby forms 

 allied to insular ones upon continental areas, requires 

 modification. To illustrate the difficult problem of the 

 absence or rarity of large, almost ubiquitous, orders in 

 oceanic islands, he selects Leguminosa;, Orchideae (the 

 table showing the absence of species or the number of 

 species of Orchidea; in various islands is extremely in- 

 teresting), and Gymnospermas ; and the concomitant rarity 

 of insects is suggested as a probable explanation so far as 

 the first two orders are concerned. We cannot further 

 notice these and other fascinating subjects dealt with by 

 Mr. Hemsley in the introduction, but must recommend 

 botanists and all interested in the subject of plant-distri- 

 bution to peruse the volume, where, in addition to the 

 information imparted by Mr. Hemsley himself, they will 

 find a serviceable bibliography of insular floras and an 

 index of islands with the names of authors who have 

 written about them. 



In the introductory notes to the several floras in the 

 second, third, and fourth parts of the book Mr. Hemsley 

 manages to convey a vast deal of information. Accounts 

 of the physical features, the history of the island, as well 

 as analyses of the vegetation are given, and he finds room 

 for illustrative e.xtracts from the works of travellers who 

 have visited the islands. Many interesting subjects crop 

 up in these — for example, the question of the sandal-wood 

 in Juan Fernandez ; but space forbids our noticing them. 

 It needs, however, little examination of this portion of the 

 book to convince one of the genuine character of the work 

 which has been put into the preparation of the floras. 

 The synonymy, the distribution, the critical notes, and the 

 general information regarding each species, all testify to 

 a conscientious search after completeness and accuracy, 

 the result being a thoroughly trustworthy record of what 

 IS at present known regarding them. One point we may 

 criticise unfavourably. We notice Mr. Hemsley has 



adopted the system of writing all specific names with a 

 commencing small letter. This, though a prevailing 

 custom with zoologists, is an innovation in botanical de- 

 scription in this country, and without discussing methods 

 of nomenclature, which would be beside our purpose here, 

 we would simply say that we do not agree with Mr. 

 Hemsley in admiring it. 



We have only been able to touch upon a few points 

 in this excellent volume, sufticient, we hope, to indicate 

 its importance. Problems of plant-distribution meet us 

 frequently throughout the volume, and Mr. Hemsley's work 

 is a most important contribution towards their solution. 

 Of especial value is his treatment of the subject of the sea 

 and birds as factors in distribution. A somewhat dis- 

 jointed character in the book and frequent repetition are 

 defects which are perhaps inseparable from the method 

 of its preparation. For inequalities the author apologises, 

 and the merit of the book as a whole fully atones for 

 them. Mr. Hemsley's deservedly high reputation as a 

 systematic botanist, confirmed by his " Botany of Central 

 America," now approaching completion, is still further 

 enhanced by this his most recent work. 



We may add that the volume is illustrated by many 

 excellent plates, chiefly drawn by Miss Smith. 



Besides bearing witness to the good fortune which 

 placed the making of botanical collections during the 

 voyage of the Challenger in the hands of so able a 

 naturalist as Mr. Moseley, the volume testifies in a very 

 emphatic manner to the inestimable value of our national 

 herbaria, especially that at Kew. Collections of plants, 

 small and incomplete in themselves, are there accumulated 

 ready for use when occasion requires, forming the mate- 

 rial from which such volumes as this we notice may be 

 constructed. We cordially join Mr. Hemsley in his hope 

 that his work may direct attention to the nature and 

 extent of the observations required from travellers for the 

 advancement of our knowledge of the subject of plant- 

 distribution, and we may conclude with one other aspira- 

 tion. There is at present no authoritative book in our 

 language on the subject of botanical geography, and too 

 many of the phytogeographical works published nowadays 

 are purely statistical compilations. Is it, then, too much to 

 expect from the pioneer in the philosophical treatment ot 

 plant-distribution, Sir Joseph Hooker, whose name is in 

 so special a manner associated with the subject of insular 

 floras, a comprehensive work on botanical geography 

 such as he alone could write 1 We hope not. 



HALS TED'S " ELEMENTS OF GE OME TR Y " 

 The Elcinen/s of Geometry. By G. Bruce Halsted. 

 (New York : John Wiley and Sons, 1885.) 



\ /I R. HALSTED is already favourably known to 



»• » J- English mathematicians by an excellent " Ele- 

 mentary Treatise on Mensuration " (published in the 

 summer of iSSi), and by one or two carefully compiled 

 bibliographies in the American Journal of Alathematics. 

 The faithful chronicler records of Tom Tulliver that he 

 called his Manual of Geometry "the exasperating 



Euclid," a title richly deserved if his desire to be ex- 

 cused the "doing" of it were really based upon the 

 reason he assigned, viz. " It brings on the toothache, I 

 think." Now we have not an annotated copy of the " Mill 



