458 STATE rOMOI.OGICAL SOCIETY. 



working on a certain kind of plant, 'wlien straightway he announces that bees 

 do not work on that species. Perhaps the bees did work at otlier times of days; 

 if not, pcrliaps they worked in otlier seasons or in other locations. Examples 

 could Ijc found to illustrate the above supposed cases. Pisuni saiicum. the 

 common pea in England, was perfectly fertile without the aid of insects. 



EARLY MATURITY (lAIXED. 



I have said that plants crossed with a foreign stock were, in a great majority 

 of cases later, larger, heavier, more vigorous, or better able to endure crov.ding 

 by other plants. Tliey also endure inclement weatlicr better. In another re- 

 spect Mr. Darwin has shown their superiority. In 50 cases the "period of 

 ilowering of the crossed and self-fertilized plants was recorded. In 44 of them 

 a crossed plant ilowercd first either in a majority of the i^ots or in all ; in nine 

 instances a self-fertilized plant Ilowercd first, and in live the two lots flowered 

 simultaneously. One of the most striking cases is that of Cyclamen, iu which 

 the crossed plants flowered some weeks before the self-fertilized in all four pots 

 during the two seasons." In some cases, as with Lupinus luteus and Clarkia 

 elcgans, the crossed and the self-fertilized plants in height were to each other as 

 100 to 82, yet Ckirkia flowered first. 



?^umerous ex])erimcnts showed that the crossing of one flower with that of 

 another on the same plant, seldom if ever docs any good. All the flowers are 

 subjected to the same conditions. In tables given, "in 35 out of 50 flowers fer- 

 tilized by pollen from a distant plant yield more, sometimes many more seeds 

 than flowers fertilized with their own pollen, and they commonly set a larger 

 proportion of cajisules." 



Considering all tlie facts brought forward, "it is difficult to avoid the sus2)i- 

 cion that self-fertilization is in some respects advantageous," though he says, 

 if this be really the case, the advantage is quite insignificant compared with 

 that from a cross with a distinct plant, and especially with one of a fresh stock. 

 In ten out of sixteen cases the self-fertilized seeds were either superior or ecpuil 

 to the crossed in weight. This the author partially accounts for "by the self- 

 fertilized capsules containing fewer seeds," wliich on this account had a better 

 chance to receive an a])undant su])])ly of nutriment. 



EFFECT OX GERMINATION". 



In twenty-one cases a record was kept of the relative period of germination 

 of crossed and self-fertilized seeds. In one case the seeds germinated simulta- 

 neously ; in ten cases the self-fertilized seeds germinated before the crossed, 

 and in the other ten the crossed seeds germinated first. After knowing the 

 great advantage to be derived from cross-fertilization, we are prepared to under- 

 stand that lioney is placed in flowers as wages to pay insects for serving the 

 plants. The gay colors and odors are advertisements to call the attention of 

 insects to the ricli supjflies of food in store for them. Saunders, of Canada, 

 cut off tlie petals of raspberries, and by so donig made it difficult or impossible 

 for the bees to find honey. "Almost every fruit which is devoured by birds 

 presents a strong contrast in color with the green foliage, in order that it may 

 bo seen and its seeds freely disseminated." 



NATURAL PROVISION FOR CROSSING. 



Among many other topics of interest Mr. Darwin gives part of a cha])tcr on 

 the means Avhich favor or ensure flowers being fertilized with pollen from a 



