262 THE FLORAL WORLD AND GARDEN GUIDE. 



The purpose of this paper being, however, entirely practical, we 

 purposely avoid all further reference to the different theories pro- 

 mulgated on the manner in which impregnation is effected ; it is 

 sufficient to show that, unless the pollen reaches the stigma, no 

 perfect seeds will be ripened — an assertion easily verified by cutting 

 out the anthers of the lily, or any other flower, as soon as it expands, 

 when the seed-vessel will be found to wither away ; and if, in some 

 few cases, it does become considerably developed, it will either yield 

 no seed, or only such as have no productive power. If, however, 

 after the stamens are removed, others from a flower of the same, or 

 of another species, are dusted on the stigma, the seed-vessels will 

 swell, and eventually ripen its seeds, exactly as in the case of those 

 blossoms from which their proper stamens had not been artificially 

 removed. In this consists the whole art and mystery of cross-breed- 

 ing. But simple as the actual conveyance of the pollen of one species 

 to the stigma of another may be, certain precautions are necessary 

 to success, and if we desire to control the result, certain laws must 

 be complied with ; but which, to speak frankly, we attach less 

 importance to, as the results are often of the most contrary character, 

 One or two of these laws are, however, so natural, that they cannot 

 give rise to the smallest doubt. 



1. No plants which do not belong to the same natural order, can 

 by any possibility be made to intermingle. The absurd stories 

 related of the origin of Willmore's double pelargonium (Surprise), 

 which was said to be a mule between a geranium and a hollyhock, 

 and of some other hybrids, need no refutation. 



2. No plants which do not form part of the same genus can be 

 united by cross-breeding. This law may at first sight appear to 

 admit of many exceptions ; but it is highly probable that, in many 

 instances in which a reputed union has taken place between plants 

 of two distinct genera, a further examination would prove that two 

 Kenera had been improperly separated, and did in reality constitute 

 but one. Should, however, the statement with regard to the recently 

 originated Cheiranthus Marshallii, which is said to be the offspring 

 of the Cheiranthus ochroleucus, crossed by the pollen of Erysimum 

 Perofskianum, prove true, this law would have to be relinquished, 

 for of the wide distinction between these two genera, there is no 

 doubt whatever. 



3. Even among species belonging to the same genus, it is only 

 those of similar structure which will yield hybrids. Thus the goose- 

 berry and currant, though both belonging to the genus Bibes, have 

 never been made to unite. It has been supposed that union can only 

 take place between these species in which the pollen grains are of the 

 same size ; and should this supposition be confirmed, a preliminary 

 microscopic examination of the two varieties of pollen would enable 

 us to judge of the probability of obtaining hybrids between any two 

 species. 



Where no natural hindrance exists to the union, the following 

 precautions are all that are necessary to success. 



1. The anthers or pollen bags of the plant which we desire to 

 impregnate artificially, should be removed immediately on the expan- 



