174 



REACTION-INTENSITIES OF STARCHES. 



Phaius and Miltonia, there is exceedingly little between 

 Phaius and Cymbidium. Obviously, from what is mani- 

 fest by the curves generally of these charts, this resem- 

 blance must be seeming rather than actual, and due to 

 faultiness in the methods of experiment and charting. 

 That the Amaryllis and Phaius starches differ far more 

 than is indicated by the composite curves is shown by the 

 records of the velocity reactions (Charts D 1 to D 21, and 

 D 574 to D 594), and it is obvious that in the construc- 

 tion of composite charts the recognition of such differ- 

 ences is essential to even an approximately accurate 

 presentation of the reaction peculiarities of any starch. 

 It will probably be found that taxonomic differences of 

 much value will be brought out by differences in the ratios 

 of the reaction-intensities of different pairs or combina- 

 tions of certain pairs of reagents, and there undoubtedly 

 yet remain many reagents that can be employed to advan- 

 tage in these studies, it being not improbable that the 

 differences in reactions of a very few reagents may be 

 specific in the differentiation of certain genera, as has 

 been found, for instance, in the tests for proteins, all 

 proteins responding to certain of the protein tests, but 

 some only to certain tests to which others do not respond. 

 Similar restricted methods of differentiation are by no 

 means rare even to the systematist. Then again, in com- 

 paring these curves it will be seen that no less than 7 of 

 the 31 reagents have, apparently at least, proved useless 

 because of the energy with which they cause gelatiniza- 

 tion. Modifications of the strengths of these alone, or 

 in conjunction with the other reagents, may elicit generic 

 differences of such a character as to indicate the wide 

 separation of these genera. 



These composite charts were studied individually 

 in Chapter III, Section 6, of the comparisons of the 

 reactions of the members of each set of parent- and 

 hybrid-stocks, and two or more of them were considered 

 comparatively whenever there were two or more sets 

 belonging to the same genus. The main object in these 

 studies was to bring out the relations of the hybrids in 

 their reactions, individually and collectively, to one or 

 the other or both parents. If now these charts are stud- 

 ied collectively, with especial reference to the relation- 

 ships of the hybrid curves to the parental curves, much 

 data of comparative interest will be elicited that is likely 

 to be missed otherwise. When the parental curves run 

 very closely together, the hybrid curve tends to similar 

 closeness; but when the parental curves tend to separa- 

 tion, and especially with variance in their courses, the 

 hybrid curve may tend to follow the curve of one or the 

 other parent, to be intermediate, or to be more or less 

 distinctly independent of both parental curves. Inter- 

 mediateness is much more of an exception than a rule, 

 and therefore except in few instances is far from being 

 a criterion of a hybrid. (See also Tables F and H.) In 

 Hippeastrum (Charts E2 to E4), Narcissus (Charts 

 E 13 to E 24), Iris (Charts E 30 to E 33), and Bichardia 

 (Chart E 40) the parental curves tend in each group and 

 genus to marked closeness in their positions and courses, 

 and the hybrid curves similarly tend to closeness to the 

 parental curves, but varying from reaction to reaction 

 in their parental relationships. When the parents are 

 well separated species, as in Hcemanthus (Chart E 5), 

 Crinum (Chart E 9), Nerine (Charts E 10 to E 12), 

 Narcissus (Chart E14), etc., and the parental curves 



are generally well separated and somewhat variant in 

 their courses, though on the whole conforming to generic 

 types, the hybrid curves tend to equal or greater degrees 

 of variance. And when the parents are representatives 

 of different genera, as in the Amaryllis-Brunsvigia 

 group (Chart B 1), or of subgenera or subgeneric groups, 

 as in Hcemanthus (Chart B 6), Crinum (Charts E7 

 and E 8), and Begonia (Chart E 36) — where the paren- 

 tal curves are not only well separated but tend to more 

 or less markedly different courses — ^the hybrid curves 

 show their greatest variabilities in their relations to the 

 parental curves, in some instances tending to have in 

 general marked closeness to the curves of one parent, in 

 others to have a position of intermediateness which is 

 usually closer to one of the parents than to the other, and 

 in others to have a more or less wide departure from 

 both parental curves. When there are two hybrids of the 

 same parentage, as in Amaryllis-Brunsvigia (Chart El), 

 Nerine (Charts ElO and Ell) and Narcissus (Chart 

 E 13), the hybrids of each pair of parents tend to differ 

 less from each other, as a rule, than the parents differ 

 from each other; unless, as in case of Amwryllis-Bruns- 

 vigia, the parents are so far separated as to give well 

 separated curves, in which case the curves of the hybrids 

 may not only be quite at variance with the parental 

 curves, but also be distinctly better separated from each 

 other, and show even more marked differences from the 

 parental curves than the latter show in relation to each 

 other. 



In a number of sets of parent- and hybrid-stocks 

 studied a given parent is found to be the seed parent in 

 one set and the poUen parent in another, or the seed 

 parent or the pollen parent in both sets, but with an as- 

 sociated parent that is different in each of the two sets — 

 as in Hcemanthus (H. hatherince, which is the seed parent 

 in two sets, the pollen parents being different) ; Crinum 

 (0. moorei, C. zeylanicum, and C. longifolium, which 

 are differently paired in the three sets) ; Nerine (N. 

 samiensis corusca major) ; Narcissus {N. poeticus or- 

 natus, N. poeticus poetarum, N. abscissu^, N. albicans, 

 N. madame de graaff, and N. triandrus albus) ; Lilium 

 {L. martagon album and L. maculatum) ; 7m (/. iberica 

 and I. cengialti) ; and Calanthe (C vestita var. rubro- 

 . oculata) . In connection therewith many interesting 

 features have been recorded in the histologic and polari- 

 scopic properties and in the reactions with heat and 

 various chemical reagents which show most varyiag trans- 

 missibilities in both kind and degree of parental charac- 

 ters to the hybrid, but a detailed review is not necessary 

 and is prohibited by want of space in an already too volu- 

 minous report. The most important of such data will be 

 found presented for the most part and in succinct form 

 in Chapter III, and in detail in Part II, Chapter I, under 

 the appropriate headings. 



4. Seeies of Chaets. 



The various charts of the reaction-intensities are re- 

 ferred to particularly or incidentally with frequency 

 throughout Part I, and it was found in the final arrange- 

 ment of the report that it was desirable chiefly for conven- 

 ience of reference to bring all of them together in one 

 section. In addition to these a series, F 1 to F 14, is in- 

 cluded, but which belongs in the next chapter, in several 

 of which certain reaction-intensities are also recorded. 



