148 



The Journal of Heredity 



canary bird, and have produced hybrid 

 offspring," he naively comments, "if 

 man had not furnished them the oppor- 

 tunity to come to know each other more 

 intimately?" He then goes on to 

 remark upon the possibility of plant 

 hybrids having been similarly produced 

 in botanic gardens, between related 

 plants, which had thus been brought 

 into accidental proximity to one another 

 and says : 



"Because I was long since convinced 

 of the sexuality of plants, and had never 

 doubted the possibility of such an un- 

 natural procreation, I, therefore, let 

 myself be deterred by nothing from 

 instituting experiments on the subject, 

 in the good hope that I might perhaps 

 be so fortunate as to bring into existence 

 a hybrid plant. After many experi- 

 ments carried on in vain with several 

 kinds of plants, in the past year, 1760, 

 I got so far in the case of two different 

 ■species of a natural group, Nicotiana 

 paniculata and Nicotiana rustica, that I 

 fertilized with the seminal dust (pollen) 

 of the former, the ovaries of the latter, 

 obtained perfect seeds, and from these, 

 in the very same year, have raised young 

 plants." 



Some twenty of these hybrids came to 

 maturity, and were found to occupy an 

 almost exactly intermediate position 

 between the two parents, with respect to 

 all of their characters examined. Un- 

 fortunately, these hybrids were com- 

 pletely sterile, and Koelreuter adds this 

 odd remark: "This plant is thus in a 

 real sense, an actual, and so far as is 

 known to me, the first botanical mule 

 which has been produced by art." 



Koelreuter made, besides other crosses 

 between species of Nicotiana, crosses 

 between species of Kedmia, pink {Dian- 

 thus), stocks [MaUhiola), dogbane 

 (Hyoscyamus) and burdock (Verbas- 

 cum). He ascertained the fact, that in 

 general only nearly related plants, and 

 not always even these, can be crossed. 

 He determined experimentally the fact 

 that if the stigmas of flowers are pol- 

 linated at the same time by their own 

 and by pollen from another species, that 

 fertilization is effected by the former, 

 which would account for the compara- 



tive rarity of "species hybrids" in 

 nature. Koelreuter also made the very 

 important discovery, the explanation of 

 which was not furnished until much 

 later, that the continued self-pollina- 

 tion of hybrids finally results in the 

 re-appearance of the original parental 

 forms. 



His ideas regarding fertilization are 

 interesting. He thought that a plant 

 was formed by the fusion of two fluid 

 materials of different sorts. The pre- 

 potence of the one parent over the other, 

 where it occurred, was ascribed to the 

 fact that, "since these materials are of 

 different sort, or in their essence are 

 different from each, other, it is easy to 

 comprehend that the strength of one 

 must be different from the strength of 

 the other." 



MISCELLANEOUS EXPERIMENTvS REGARD- 

 ING SEX IN PLANTS 



Camerarius and Koelreuter stand as 

 the two great landmarks in the history 

 of scientific plant breeding up to 1766. 

 While these two were the only investi- 

 gators whose contributions to our know- 

 ledge of sex in plants were extensive or 

 fundamental, it is of interest to know 

 that the first person who is reported to 

 have actually crossed plants artificially, 

 was an Englishman named Thomas 

 Fairchild, who, according to Bradley 

 (1, p. 16), crossed two kinds of pinks in 

 1719. The cross in question was known 

 still to gardens, one hundred years later, 

 as " Fairchild 's Sweet William," never- 

 theless, as Focke says (p. 430): "This 

 success in artificial fertilization was 

 never utilized for science, nor does it 

 appear to have given gardeners any stim- 

 ulus to further investigations." 



Two years earlier than this, Bradley 

 himself (1, p. 20) had removed the 

 anthers from the flowers of twelve tulips 

 which he had planted in a remote place 

 in his garden, and had found that they 

 produced no seeds, while some four 

 hundred tulips planted elsewhere in the 

 garden and left intact, produced seeds 

 freely. 



Twenty years later, in 1739, James 

 Logan, an American citizen of Irish 

 birth, and at that time governor of 



