IMPORTANCE OF PLANT VARIATION. 85 



it produces only pistillate or staminate flowers. The radish when grown 

 in a crowded place will throAv up seed spikes from a nearly fibrous root 

 thus completing its cycle in a few months while when grown normally 

 with plenty of room it produces a large fleshy root which can be kept over 

 winter and planted for seed the next spring, hence making it an annual 

 or biennial, depending upon its proximity to other plants. 



Hybridization, contrary ^o a first thought, does not play a very im- 

 portant part in the origin of plant species. Bailey says : "Not one 

 known proof can be found that shows that nature ever produced a new 

 species by hybridization," but species have crossed producing a varia- 

 tion from its parents which through successive crossings and natural 

 selections have produced forms of rather wide divergence. 



The possibility of plants being influenced by the above agencies is of 

 the utmost importance to the horticulturist. It is the foundation upon 

 which horticulture is built and without it the science could not exist. 

 If plants would grow and produce progeny exactly like their parents 

 one person could raise fruit and vegetables as good as any other as far 

 as varieties are concerned. But this is not so. Plants do vary and 

 yield admirably to the wishes of the horticulturist, thus it opens to 

 him a wide field for operation. Much important work has been done 

 along the line of amelioration of plants, and as the horticulturist be- 

 comes acquainted with the morphology and physiology of the plant, he 

 becomes more systematic in the performance of this work. Not only 

 is it important to know what is possible to do with wild plants, but 

 what improvements can yet be wrought with those plants already under 

 cultivation. 



Leaving now the horticulturist to select for himself other benefits 

 which he can find in plant variation, let us notice whether the botanist 

 is concerned in this matter. 



It has not been many years since, that most botanists considered 

 species as fixed groups, and that they were always as they now are; 

 but as the theory of evolution gained acceptance, most botanists have 

 changed their views and now look at species as variable things; as varia- 

 ble as plants themselves. 



If we accept evolution in the development of animal forms it seems to 

 me to be much easier to acce]»t it as it concerns plant forms. The evo- 

 lutionist looks at the whole plant creation as a progressive series, from 

 the beginning of the lowest unicellular form to the highest plant organ- 

 ization. It is true gaps and breaks exist at irregular intervals which 

 seem to set portions of this series ofl" as distinct groups with greater or 

 less characteristic difl'erences, but it is this fact that makes classifica- 

 tion of plants possible. It shows that the weaker connecting forms were 

 not able to survive in the struggle for existence. As the plants of a 

 given species vary, the species tends either to enlarge or diminish; the 

 same is true of the genus. It is this relation of the plant to its specific 

 name that makes ])lant variation of importance to the botanist as re- 

 gards species making. 



Although most botanists are evolutionists yet some might consider 

 species as being fixed at present. All agree that if we accept the evo- 

 lutionary theory in part of the organic world we must accept it in all. 

 If we accept it in animal life we must accept it in plant life. Bailey 

 says that, "The Darwinian theory is better adapted to an application 



