282 Self-Ster'dity in Plmns, Cherries, and Ap2)les 



of partial self-fertility are probably attributable for the most part to 

 errors. When, for instance, in the case of Coe's Golden Drop fertilized 

 by Jefferson, the record shows a few fruits formed, out of a large 

 number of flowers pollinated, the fact may mean that compatibility 

 exists in a very slight degree, and if this could be confidently asserted, 

 it would be tempting to suppose that the tree may be mosaic in that 

 respect; but conceivably some error may have occurred. Between 

 these interpretations we have at present no means of deciding, and the 

 facts can only be given as they stand. The characters of the seedlings 

 will in some cases hereafter provide a criterion. 



As regards the question of cross-incompatibility the work was begun 

 in the expectation that this was the only acceptable account of the facts. 

 The older belief implied the paradox that there are as many categories 

 as individuals; that, as a friend put it, "each lock would open with every 

 key but its own." Nevertheless the results obtained have not favoured 

 the theory of cross-incompatibility. Of clear incompatibles we have 

 found four only, Coe's Golden Drop, Crimson Drop, Coe's Violet and 

 Jefferson. But Crimson Drop and Coe's Violet are known to have 

 arisen as bud-sports from Golden Drop^ and it is not altogether impossible 

 that Jefferson had a similar origin". In apples no such case was seen. 

 Cherries have not been so fidly investigated and some records of failure 

 with certain pollens may possibly be an indication of incompatibility, 

 but pending repetition and confirmation their significance is doubtful. 

 We are thus driven to suppose that at least in plums and ajjples the 

 former belief is at least approximately true, improbable as this may 

 appear. 



The evidence from apples is not strictly ap2:)licable in this connexion, 

 for as our records relate primarily to the formation oi fruits the power 

 of the pollen in producing seeds is very imperfectly recorded. In plums 

 and cherries well-formed fruits with rarest exceptions contain developed 

 seeds, but in apples seedless fruits are common, and indeed in Duchess 

 of Oldenburg and Antonowka are almost the rule, nor doesi seedless- 

 ness necessarily involve any diminution in the size of the fruit (e.g. 



1 As to the origin of Coe's Violet, see 0. Thomas, Kev. Hort., 1870, xlii. p. 515. 

 Mention is also made of the independent occurrence of a sport, presumably identical, in 

 Trans. Hort. Soc. Vol. vi. 1826, p. 393. Another violet sport was observed by Mr Vert 

 of Ruabon {in litt.). For the origin of Crimson Drop see R. H.S.J. 1901, xxvi. p. ccxxvi. 



2 Hedriek, U. P., Plums of New York, 1911, p. 256, writes : " The parentage of the 

 variety is unknown ; Floy thought it was a seedling of Washington ; Elliott suggested 

 that it was 'from a seed of Coe's Golden Drop, which in growth and wood it closely 

 resembles.'" 



