224 PLANT-BREEDING 



corresponding smaller deviations from the average type. 

 He uses the species for stocks for grafting and had sown them 

 from seed which he had received from the southern states. 

 From one of these introduced seeds the sport had arisen. 

 There could be no doubt that it was due to a real mutation, 

 and it was manifest, also, that this had been produced be- 

 fore the introduction. But whether the deviating specimen 

 itself was to be considered as a mutant, or whether, perhaps, 

 in the original locality an old yellow ^^ariety of Mahaleb 

 cherry existed, he could not tell. It was noticed here for 

 the first time, but whether it was old or new, nobody knew. 

 It was, however, a most typical sport. Elementary species 

 among trees have not yet been given the interest which they 

 deserve. The apples, pears, hav^horns, and some others 

 have yielded numerous types, either for industrial culture or 

 for scientific description. Oaks and walnuts differ in the 

 same way, and there can hardly be any doubt that this 

 is true for a large number of deciduous and even of conif- 

 erous trees, also. A scientific distinction and industrial 

 test of these elementary species might probably lead to a dis- 

 tinct improvement of many of our forests and groves, giving 

 more uniform crops of nuts, or harder and better lumber, or 

 a more rapid growth, or more straight and less branched 

 stems, etc. A combination of the results which Nilsson ob- 

 tained by his sharp distinction of the elementary species of 

 cereals, with the possibiUties indicated by the hybrid walnuts 

 and other trees of Burbank, might open large prospects of 

 improvement in forestry. 



In many cases it is doubtful whether a sport is due to a 

 mutation or to extreme fluctuating variability. The fra- 

 grant varieties of Calla, DahUa, and Verbena may be cited 

 as instances. The first of them has already been alluded to, 

 but the production of the two others deserves a more detailed 

 description. Along the fence of his garden, in front of his 



