306 



THE GARDENER'S MONTHLY 



[Octobei- 



uses during this long time, which will balance j be but fair to charge intei-est on $112 per acre,, 

 the waiting so long for the returns, leaving ten ! instead of S75. On a calculation on this basis. 

 per cent, as the clear gain on the S75 basis. But I the forest will yield but little over six per cent. 

 as the land has been steadily growing in value | per annum, exclusive of the net value of the 

 during forty years — from S75 to 8150 — it would land. 



Natural History and Science. 



COMMUNICA TIONS. 



THE SELF-FERTILIZATION OF PLANTS. 



BY REV. GEO. HENSLOW. 



[As our readers know, much attention has been 

 given of late years to the subject of cross-fer- 

 tilization of flowers by insect and other agen- 

 cies. It is understood that many plants are 

 unable to fertilize themselves, and that others 

 which can do so, are more easily fertilized by 

 these outside agencies than by their own act. 

 A difference of opinion has grown out of these 

 facts. Mr. Darwin, Dr. Gray, and others be- 

 lieve that cross-fertilization is a benefit to the 

 plant or its race, and that the arrangements for 

 cross-fertilization were expressly designed for 

 the accomplishment of this good end. The ad- 

 vocates of this view had the advantage of nov- 

 elty and plausibility, and for a while the ground 

 seemed indisputable ; others following, failed to 

 see the good results from cross-fertilization, 

 found a great deal more self-fertilization among 

 flowers than the other party was at one time 

 prepared to grant, and discovered a great many 

 risks and disadvantages to plants dependent on 

 insect or other aid. Amongst these is the Rev. 

 Geo. Henslow, who about a year ago published 

 an elaborate paper on this logical question. 

 This paper induced a lengthy review in Silli- 

 mati's Journal^ from the pen of Dr. Gray, which 

 has been copied into the Botanical Gazette, and 

 probably other papers in this country. Prof. 

 Henslow sent the following reply to SiUiman''s 

 Journal, which the editor, Dr. Gray, though 

 under no obligation to do so, kindly promised to 

 insert. Subsequently an abstract of Dr. Gray's 

 criticism appeared in the London Gardener'' s 

 Chronicle, and Prof. Henslow justly apprehend- 

 ing that the reply would be better understood if 



immediately following the criticism, sent a copy 

 of the reply, which was published in the Gar- 

 denerh Chronicle, the following week. Dr. Gray 

 now declines to publish in Silliman\s Journal 

 Prof. Heuslow's reply. 



If the Gardener'^s Chronicle were read by the 

 same persons in this country who i-ead Silliman^s 

 Journal, Botanical Gazette, and so forth, it would, 

 of course, be a waste of space to reprint in Silli- 

 mati^s Journal. Dr. Masters did not think the)'^ 

 were the same, or he would not have reproduced 

 Dr. Gray's remarks in the Gardener's Chronicle ; 

 nor do we think so, and thei-efore, as an act of 

 justice to a distinguished foreign scientist, we 

 give space for the reply in the country where 

 the criticism was made. — Ed. G. M.] 



"Although the Professor at first calls my essay 

 'unconvincing,' yet at the close of his remarks 

 he appears to be convinced on one, and that, too, 

 the most important point : ' Without acceding 

 to his general proposition, we are much disposed 

 to agree with the author in this essay as respects 

 some of them [i. e., weeds), that aptitude for self- 

 fertilization may have given them the advantage 

 which has determined their wide dispei'sion.' 

 This, however, at once admits that by their dis- 

 persion and by the maintaining their existence, 

 self-fertilizing plants have proved themselves to 

 be the best fitted to survive in the natural strug- 

 gle for life. This is the sum and substance of 

 my argument, and it necessarily involves the 

 accei>tance of the converse proposition, that 

 plants dependent upon insects are least fitted to 

 be dispersed and to survive. I admit to the full 

 that all conspicuous flowers are more or less 

 adapted to insect agency, but I demur to the ex- 

 pression that such flowers are ' benefited ' b}- in- 

 tercrossing. Such a term assumes self-fertiliza- 

 tion to be the standard for comparison. But as 



