THE SECRETAKY'S PORTFOLIO. 455 



Ave could not cross a flower of one Korthcru ^py api)le-trec v.'itli the flower of 

 another tree of the same variety, as they liave all come from tlie grafts or buds 

 of one seed. In like manner it would not be a cross to fertilize a flower of the 

 General Grant geranium with others of the same variety, Ijecauso all our plants 

 have come from cuttings of one parent plant, or some of its descendants. 



Many of Mr. Darwin's plants were raised from seeds which were sown at the 

 same time, near each other, Tlie best young plants from the seeds of crossed 

 flowers, and the best which came from self-fertilized flowers, were i)lanted on 

 opposite sides of the same pot, where the soil was well mixed. "In comparing 

 the two sets, the eye alone was never trusted." 



Fifteen plants of Indian corn from crossed seed exceeded in height fifteen 

 others from self-fertilized seed, as 100 exceeds 84. He experimented witli 

 plants of the common Morning Glory for ten generations, nsiiig tlie same num- 

 ber of plants from crossed plants as from those self-fertilized. Tlie average in 

 height for the ten years is as 100 to 77 in favor of the crossing. 



The flowers of this plant are freely crossed if left to themselves, exposed to 

 insects. It is, then, altogether likely that the seeds with which Mr. Darwin 

 began were from crossed flowers, yet, in the first generation, the seeds of 

 crossed plants exceeded those self -fertilized as 100 exceeds 7G. If we compare 

 the number of seeds and capsules produced in the first generation, the crossed 

 plants exceeded the others as 100 exceeds 64. The relative superiority of the 

 crossed plants is chiefly due to their producing a much greater number of cap- 

 sules, and not to each capsule containing a larger average number of seeds. 

 When self-fertilized for nine generations, the flowers were of a uniform tint, as 

 those of a wild species, while those in the beginning w'cre of various colors. 

 The crosses, so far mentioned of the flowers of Morning Glory, refer to crosses 

 of different plants raised in the same garden, year after year. After nine gen- 

 erations he introduced seeds raised at a distance, under different circumstances. 

 Plants from these were crossed with plants which had been intercrossed in his 

 garden. This cross (called the Cochester-crossed) exceeded in height the other 

 intercrossed plants of the tenth generation, as 100 exceeds 78. In number of 

 capsules, they were to each other as 100 to 57, and the capsules, in weight, as 

 100 to 51, in favor of those crossed with foreign stock. 



Here we get a most important fact, not learned by Mr. Knight, or any one 

 else, that a cross from a fresh stock increases the size of plant and its fruitful- 

 ness, probably owing to their differing somewhat in constitution or character. 

 The crossing of closely related plmits is generally an improvement over self- 

 fertilization ; hut crossing with foreign stock of the same variety is afar greater 

 imjjrovement. 



The proof of the truth of the above sentence in italics is worth untold sums 

 to the raiser of vegetables, the florist, the pomologist, to the general farmer. 



In the sixth generation of the self -fertilized morning glory, appeared a single 

 plant which conquered its crossed opponent by half an inch in height. Its 

 descendants continued vigorous and fertile, even when self-fertilized. They 

 were not profited by a cross with a distinct stock. Mr. Darwin adds that if 

 this latter part is trustworthy, it is a unique case, as far as he has observed in 

 all his experiments. 



POREIGN-CROSSED STOCK AHEAD. 



In the case of Mimulus luteus (monkey-flower), a small herbaceous ornamental 

 plant, Mr. Darwin found for three successive generations that the crossed plants 



