308 STUDIES, SCIENTIFIC AND SOCIAL 



breaks down owing to the want of any conceivable con- 

 nection between insect irritation and most of the innu- 

 merable adaptations of the parts of flowers to attract 

 insects and secure cross-fertilisation. Such are the sticky 

 glands, the elastic filaments, the springs and traps, and 

 the accurately timed motions of the poUinia in orchids ; 

 the innumerable complexities in papilionaceous flowers ; 

 the large coloured bracts in Bougainvillea, Poinsettia, and 

 many others; the flowers with tightly-closed lips, as 

 Linaria, Antirrhinum, Melampyrum, &c. ; the enlarged 

 rays of Compositse, Umbelliferye, and Caprifoliacese ; the 

 general massing of small flowers into heads, umbels, 

 corymbs, or dense racemes, so as to become conspicuous, 

 and many other characters. To these may be added the 

 negative evidence of the numerous genera and orders of 

 regular flowers, such as Campanula, Rosacese, Gentianacese, 

 and many others, which, though thoroughly adapted for 

 insect fertilisation, and whose lower petals have therefore 

 been always subject to irritations, have never developed 

 irregular flowers. In all these cases variation with 

 Natural Selection will account for the phenomena, while 

 insect irritations, even if we admit heredity, will not do so. 

 From whatever point of view we approach the question, 

 the attempt to explain floral structure and colour without 

 the aid of Natural Selection is a hopeless failure. 



The Origm of Spines and Prickles. 



In the Journal of the Linnean Society (" Botany," No. 

 208, July 10, 1894) there is an elaborate paper by Mr. 

 Henslow on " The Origin of Plant-Structures by Self- 

 Adaptation to the Environment, exemplified by Desert 

 or Xerophilous Plants," in which the author still farther 

 develops his view as to the influence of the direct action 

 of the environment unaided by selection. The only por- 

 tion of this paper on which I propose to remark is that 

 dealing with the origin of spines and prickles, on which 

 I have already had occasion to write in my book on 

 Darwinism, when combating Professor Geddes' views 

 on the same subject. Mr. Henslow imputes the spines 



