NEW VAKIETIES BY CROSSING. 27 



ihe seeds were taken from the fruit of an old bearing or graft- 

 ed tree ; and to this practice he chiefi}^ ascribed his success. 

 The many instances, howeA^er, of fine seedlings from old 

 grafted sorts, throw a shade of doubt over this theory. 



NEW VARIETIES BY CROSSING. 



A familiar instance of cross-impregnation in plants occurs 

 in the Indian corn. The pistillate or seed-bearing flowers 

 covering the young ear, are remotely situated on the plant 

 from the staminate or fertilizing flowers on the summits or 

 tassels. Hence, from this remote position, the pollen or fer- 

 tilizing dust from the summits may not certainly fall on the 

 ear ; and if difTerent sorts grow near, a mixture will proba- 

 bly result. It is well known to farmers, that if different sorts, 

 as white, yellow, and purple, are planted in the same field ; 

 or, if common and sweet corn are planted together, each 

 sort no longer remains distinct, but each ear the second year 

 is speckled with a promiscuous assemblage of white, yellow, 

 and purple, and of common and sweet corn, of various grades. 

 In fruit trees, the stamens and pistils are in the same flower, 

 and the chances of accidental mixture from other trees, be- 

 come very small, unless affected by insects, which, becoming 

 thickly dusted with powder from one flower, plunge into the 

 recesses of another, and effect a cross-fertilization. Where 

 many varieties grow in one garden, in close proximity, cases 

 of promiscuous intermixture are constantly occurring, which 

 can be developed only by raising fruit from the seedlings. 

 In the annexed figure of the pear blossom, (fig. 1,) the 

 ^f; five central organs, a, are the pistils ; 



the upper extremity of each is the 

 stigvia. The surrounding thread-like 

 organs, h, are the stamtns, surmount- 

 ed by the anthers. The anthers are 

 little bags or cases filled with the 

 pollen or fertilizing dust. When the 

 flowers open, the anthers burst, and 

 ^'o- ^' discharge the pollen on the stigma, 



which operates on the embryo fruit at its base. 



The production of new varieties is greatly facilitated by 

 cross-impregnation, or by fertilizing the pistil of one variety 

 with the pollen of another. This was performed with great 



