88 



THE GARDENER'S MONTHLY 



[March, 



in our last. We had no idea of sufificstinp; 

 that the "secretion of the nect^iry of a llowi-r 

 gets applied to a stigma." Wliat is sec-rcted hy 

 the nectaries we regard as waste, and so expressed 

 it. But Boussingault shows that sweet matter per- 

 vades the whole tissue — of the pistil, as well as of 

 other parts — and it occurred to us in view of this 

 possibility that the sweet matter might be of 

 some direct use to the plant in the i)erformance 

 of its functions, and not merely nothing but a bait 

 to allure insects. Granting that it may be of some 

 use directly to the plant, it may be in relation to 

 pollenization ; and, when deficient in the pistil, 

 an application to the stigma may supply it. All 

 this is of course hypothetical, but it is a hypo- 

 thesis suggested by Dr. Hooibreuk's experiments, 

 quite independently of any thing which he may 

 have been trying to prove. 



Honey was no doubt made for insects, but in 

 the same sense as cane sugar and molasses were 

 made for man. The cane sugar plant has "an 

 advantage " by man's use of the sweet secretion ; 

 for it has been petted and fostered so that it has 

 gained immensely in "the struggle for life." 

 Thousands' of sugar plants exist that never 

 would, but for the saccharine element. As far 

 as it goes it is a fair argument, but who would in- 

 sist that the sugar was developed for this purpose 

 and is of no direct use to the plant itself? It 

 is these considerations which make us hesitate 

 to believe that before insects Avcre created, sweet 

 secretions did not exist ; and nothwithstanding 

 the doubts of our correspondent, we think no 

 harm will result from the investigations we pro- 

 posed.— Ed. G. M ] 



QUERIES. 



Fertilization by Insect Agency. — Prof. Asa 

 Gray writes: — "We are not all of us as careful 

 and exact in our statements as Mr. Darwin is, 

 and so our language is sometimes misappre- 

 hended and sometimes needs correction. Dar- 

 win's summing up in the first edition of his Or- 

 chid-book, is : ' Nature thus tells us in the most 

 emphatic manner, that she abhors perpetual 

 self-fertilization.' In the new edition, issued this 

 year, we read : ' It is hardly an exaggeration to 

 say that Nature tells us in the most emphatic 

 manner, that she abhors perpetual self-fertiliza- 

 tion. This manifests carefulness to be within 



bounds, but does not look like giving up the 

 jirinciple. Some of us have been less careful to 

 keep the word ' j)erpotual ' perpetually in view; 

 but it has generally been implied in the whole 

 course of statement, which has recognized the 

 fact that most flowers have a chance, and majiy 

 a predominant chance, for self-fertilization. Ikit 

 this does not at all falsify the declaration that 

 'showy, fragrant, honey-hearing flowers are ar- 

 ranged for cross-fertilization.' If anybody wants 

 to see a good demonstration of that, let him read 

 the second chapter of Darwin's new book on the 

 effects of close and cross-fertilization in plants, 

 or a summar}' of it in the March number of the 

 American A(/ricuUuris(. Here is a plant aljun- 

 dantly capable of self-fertilization, which close- 

 fertilizes when covered, but is, in fact, freely 

 cross-fertilized in nature. Mr. Darwin proves, 

 by a course of experiments, that the crossing is 

 a benefit, and a great benefit ; and the inference 

 is almost unavoidable that these plants could not 

 go on indefinitely without it. 



" It is now clear, however, that there is more 

 self-fertilization than was at first supposed. H. 

 Miller has largely shown this, while at the same 

 time contending for the absolute need of cross- 

 fertilization ; just as you yourself, Mr. Editor, 

 have largely shown it, while contending that 

 cross-fertilization is of no account. But I think 

 you will soon agree that cross-fertilization is of 

 account, and that showy, odorous, nectariferous 

 flowers are adapted for it, notwithstanding ever 

 so much self-fertilization." 



[In the "Detroit" paper the text taken was 

 this, "All plants with conspicuously colored 

 flowers, or powerful odors, or honeyed secretions 

 are fertilized by insects; therefore, before honey- 

 feeding insects existed, the vegetation of our 

 globe could not have been ornamented with 

 bright colored flowers." This is the point we 

 ventured to differ from. If the proposition now 

 made that these flowers are so arranged that 

 cross-fertilization is possible, and that it occa- 

 sionally does occur, is not inconsistent with the 

 point we ventured to question in the above quo- 

 tation, we have of course nothing further to say. 

 We have never said cross-fertilization was of no 

 account, but that we do not regard it as proved, 

 —Ed. G. M.} 



The Verbena Rust. — We have always felt 

 that the Verbena Rust must be of fungoid origin, 

 because all the attendant phenomena are fun- 

 goidal, and there is no character whatever that 



