160 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



provides tlie student with numerous questions at the end of the chapters, 

 and also with others, suggesting thought and investigation incidentally 

 in the text. It is well illustrated throughout, and the final chapter on 

 Ecology is a distinct and valuable feature; but the fact that " Adapta- 

 tion by response " is the real " cause " of variations might be more 

 strongly emphasized ; there Mr. McCallum proved experimentally that 

 the dissected type of submerged leaf in Proserpinaca was the result of 

 supersaturation by water. 



A few other suggestions might be made. No mention appears to 

 occur of transpiration being especially due to red and violet rays of the 

 spectrum (p. 122). Spinescent processes are shown by Ecology to 

 be the direct result of drought, not formed specially as a protection 

 against brov/sing animals (p. 185). Camels live on the thorny bushes 

 of desert countries. Has it ever been proved that pollen of anemo- 

 philous plants is lighter than that of others? (p. 246). 



The figure of the corymb is inexact. If the bracts are opposite, each 

 pedicel would be a secondary peduncle and bear a pair of pedicels, as in 

 Caryophyllaceae (p. 230). 



The leaves of Ranunculus Ficaria ai'e not strictly opposite, but 

 alternate on opposite sides of the axis. This is suggested to be a result 

 of the single cotyledon (not mentioned). 



Self-pollination (following Darwin's error) is described (p. 217) as | 

 inferior in its effects to cross-pollination; but examples on pp. 214, 237, 

 238 prove the contrary. The diagram of a root-tip (p. 160) would 

 apply to a Monocotyledon, in which the root-cap has its origin inde- 

 pendent of the initial cells of the root, not of a Dicotyledon, rightly 

 described in the text. 



Speaking generally, the book is an admirable one, especially for 

 encouraging close, accurate, and abundant observation on the part of j 

 the student. . j 



"Charles Darwin and the Origin of Species; Addresses, &c., in ' 

 America and England." By E. B. Poulton, D.Sc, M.A., F.E.S., &c. 

 8vo., 302 pp. (Longmans, London, 1909.) 7s. 6d. net. j 



The book contains the following: — Fifty Years of Darwinism; The j 

 Personality of Darwin; The Darwin Centenary at Oxford; Darwin and | 

 the University of Cambridge ; Colour and Mimicry ; Letters from | 

 Darwin to Eoland Trimen; and four appendices. The first address | 

 treats of the following, amongst other matters: — Erasmus Darwin and j 

 Lamarck, The Influence of Lyell, Foreshadowings of Natural Selection, | 

 The Publication of the Darwin- Wallace Essay, Echoes of the Storm, | 

 Attacks of Owen and St. G. Mivart, Lamarck's Hypothesis and the | 

 Hereditary Transmission of Acquired Characters, &c. | 



Prof. Poulton called Darwin's and Wallace's communications a I 

 " joint essay," but in the " Journal of the Linnean Society " they are | 

 perfectly distinct. There were three papers — (1) " Extract from an 

 Unpublished Work on Species by C. Darwin"; (2) "Abstract of ^ 

 Letter from C. Darwin "; and (3) " On the Tendency of Varieties to 



