u 



by iirogressive cultivators whose connected territory presents sucli 

 varied conditions of soil and climate as ours. The existence of regions 

 in the United States whose cultural possibilities have as yet been only 

 joartially tested gives to the work of exploration a wide range, with 

 reasonable hopes that each new territory explored will yield varieties 

 more suited to some one at least of the numerous localities than those 

 already in cultivation. 



It is particularly in this branch of introduction work that the repu- 

 table seed and nursery firms of the country have rendered a most 

 important service; plainly because a superior variety of a well-known 

 plant possesses, immediately upon introduction, a market value which 

 a new species may not. The fact must not be lost sight of, however, 

 that to search out these new varieties and secure them requires the 

 labor of trained explorers or specialists in the particular branches of 

 plant industry. The chances of profitable return within a reasonable 

 length of time are not such as to induce seed firms to undertake the 

 work of exploration in the absence of laws protecting the importer of 

 a new variety. 



If the ^ork of this character were left to individual enterprise, only 

 occasional expeditions could be expected, and no comprehensive explo- 

 ration of the cultivated territory of the globe would be undertaken. 

 This branch of the work should in no way interfere with the interests 

 of individual seed anl nursery firms, since the quantities distributed 

 must necessarily be barely large enough to call the attention of culti- 

 vators to the plants, and the demand which it would be the object of 

 the experiments to create would have to be met by importations or 

 IKoi^agations by the seed or nursery firms themselves. 



THE COLLECTION OF SPECIES FOK BREEDING PURPOSES. 



The work of plant introduction, when considered from the standpoint 

 of the plant breeder, assumes a new and most important aspect. The 

 Eev. Thomas Gulick,* whose papers ui^on evolution have attracted the 

 attention of no less a biologist than Eomanes, has pointed out the value 

 of sexual sterility' as a barrier which tends to prevent the obliteration 

 of new characters developed by variation from a parent type. Should 

 an individual plant showing most marked x:)eculiariti(^s distinguishing 

 it from its progenitors be allowed to breed with other offspring from 

 the same parents which show no such peculiarities, it would produce 

 progeny more and more like the parent form, i. e., the peculiarity, be 

 it ever so desirable, will be obliterated sooner or later by interbreed- 

 ing. If, however, this peculiar offspring is more or less sterile to its 

 immediate relatives, it will be prevented from interbi eediug. Should 

 its own pollen be i)repotent, for example, to that from the parent stock, 



* First clearly poiuted out by Rev. John Thomas Giilick in hiS paper ou Divergent 

 Evolation thronf;;li Cumulative Segregation, in Jour. Linn. Soc., Vol. XX, Zoology, 

 p. 189; Dec. 15. 1^87. 



