INTRODUCTION. 



21 



Bibilities of the breeder than those of Burbank. In re- 

 ferring to the results obtained by crossing and selection 

 in general, he states ( New Creations of Plant Life, Bar- 

 is nud, [912, 216) that " there is no barrier to obtaining 

 Fruits of any size, form, or flavor desired, and none i" 

 producing plants and flowers of any form, color, or fra- 

 grance. All that is needed is a knowledge to guide our 

 efforts in the right direction, undeviating patience, and 

 cultivated eyes to detect variations in values." 



If starch characters are heritable they should, in 

 order to meet theoretic requirements, exhibit peculiari- 

 ties of inheritance corresponding to those observed in 

 gross and microscopic anatomic plant characters. This 

 deduction will he found to have ample justification in the 

 results of this research. Herein it will be found that the 

 starches of the hybrids frequently exhibit in histologic, 

 polariscopic, and physico-cheniie properties some degree 

 of intermediateness between the parents, usually nearer 

 one or the other. In any given hybrid certain of the 

 properties may be exactly or practically exactly inter- 

 mediate, and other properties may be identical with the 

 corresponding properties of one or the other parent. In 

 many instances one or more of the characters of the 

 hybrid, such as the relative number and the types of 

 compound grains, the degree of figuration, the regu- 

 larity or iregularity of the forms of the grains, the 

 characters of the hilum, the distinctness and size of tin 

 lamellae, the polariscopic properties, the temperature of 

 gelatinization, the aniline reactions, and the qualitative 

 and quantitative reactions with the various chemical reag- 

 ent-, were developed or manifested in degrees beyond 

 the parental extremes. Moreover, peculiarities of various 

 kinds were observed at tune- in the hybrid that were not 

 apparent in either parent. In so far as these results go 

 they are, in general, in entire accord with the experience 

 of the plant ami animal breeder and with unquestionable 

 statements of literature. 



The doctrine of intermediateness of the microscopic 

 characters as set forth in a preceding section is not war- 

 ranted by the literature of naked-eye characters and 

 iposed to the results of the work with starches. This 

 led to supplementary studies of the macroscopic and 



•scopic characters of parent- and hybrid-stocks 

 which compose Chapter IX of Part II. It seems clear 

 upon general grounds that if character- of the starch of 

 the hybrid may be intermediate, dominant, recessive, 

 blended, modified, developed beyond the parental ex 

 tremes, new characters developed, etc., corresponding 

 phenomena should be exhibited by the tissues. It was 

 expected when this part of the research was planned that 

 in the case of each plant both starch and tissues could 

 be studied coincident! v and compared, but this was found 

 to be impracticable; therefore the studies of the plant 

 li-sues were carried on as an independent but corn 

 research. Here, as with the starches, excepting Tpomaa, 

 the specimens of both parent- and hybrid are of 



the first generation that has been perpetuated from vear 



ar l>\ the propagation of tubers, pseudo tubers, rhi- 

 zomes, 1/nllis, bulbils, etc. Both of the parent- and the 



hybrid-stocks of ijiuncm were grown from .Inch 



breed true. The hybrid i- of the offspring 



annual seed planting- -nice L908, and probabl] repri 



the sixth or seventh m the line of descent. The 

 were obtained from the originator of the hybrid, and the 

 other Btock from reliable plant-growi 



The different specimens of starches were prepared 

 from a number (varying u.-ualh from 5 or to to loo 

 or more) of bulbs, rhizomes, etc., -,, that the prepara- 

 tions ma\ he taken as n-pre.-ent.ing a fair mean ; but with 

 the plant,- used I upply of tissue we were dependent 



in ea< i ually upon one or two specimens which 



may he taken to be of about the average or fairly 

 entative. 



In selecting the material from the different plfl 

 for the microscopic preparations the precautionary meas- 

 ure- promulgated by Macfarlane (page l) to -■ 

 comparative results were as far a- carefully 



followed out. Inasmuch as there is a I . for indi- 



viduals of a spi en when grown under the same 



conditions, to vary in one or more of their characters 

 from the average degree and manner of development, 

 macroscopically and microscopically, it is manifest that 

 in a comparative examination of parent- and offspring 

 there should be studied either the actual parent- and a 

 selected typical specimen of the hybrid that exhibits the 

 average mean properties of the hybrids, or typical speci- 

 mens of both parent- and hybrid-stocks. When neither 

 is practicable, as was the case in the present inquiry, 

 there are probabilities that the relative values of the 

 various characters may not be wholly correct, as for in- 

 stance, a given character of the hybrid may be inter- 

 mediate but nearer one or the other parent instead of 

 being exactly mid-intermediate, or via versa, as might 

 be the case had the plants been very careful! 

 upon the basis of the specificity of intermediati 

 On the other hand, it goes without saying that in the 

 selection of the hybrid the assumption that the one hav- 

 ing most nearly pro] hat are exactly intermediate 

 between those of the parents is a typical hybrid is certain 

 to lead to the worst of pitfalls, because it of nee. 

 implies thi ! inheritance is a sine qua non; there- 

 fore, as a corollary, that having a given hybrid it^ 

 parentage might positively he detected by tie 

 of species that have characteristics such as would meet 

 the theoretical requirements of intermediateness in the 

 hybrid. It is obvious that such a plant might be far 

 more undesirable ami even absolutely unreliable for com- 

 parative purposes than one that has the least degn 

 intermediateness, because the latter but not the former 

 may typify the mean of the hybrid charai ' The 

 results of various investigations fully justify the state- 

 ment that intermediateness may be absolutely misleading 

 as a criterion in the recognition of hybrid-. 



S. ETnit-Charai rERS lnd [Jnit-Character- 



l'll.XSES. 



The term character is used throughout this research 



in a conventional sense to signify any property that 



