570 



DATA OF PROPERTIES OF STARCHES OF PARENT- AND HYBRID-STOCKS. 



The hilum becomes distinct, attended by the forma- 

 tion of a bubble, in a majority of the grains. The la- 

 mellae are distinct at first, but later are somewhat 

 obscured. Gelatinization begins at the hilum and pro- 

 gresses according to two methods. In the first, which is 

 seen in a majority of the grains, the portion of the grain 

 immediately surrounding the hilum, which probably 

 represents a primary starch formation, is partially separ- 

 ated from the secondary starch by a refractive fissure, 

 and both the primary and the secondary portions of the 

 grain are divided by refractive fissures into concentric 

 portions of varying size ; they gelatinize and swell at the 

 same time; the primary grain following closely the en- 

 largement of the secondary starch, the material becomes 

 at first more, then less refractive, and loses its dense 

 appearance, and finally the line of demarcation between 

 primary and secondary starch also disappears. In a few 

 grains the primary starch is divided by coarse stria? into 

 a number of coarse, cylindrical granules, which, as the 

 secondary starch swells, likewise swell and line its inner 

 border until nearly the end of the reaction, when they 

 disappear as the rest of the grain loses its structural 

 appearance. In the second method, which is seen in 

 a moderate number of grains, 2 furrows extend trans- 

 versely or obliquely from the hilum on either side to 

 the margin and the starch distal to these and the hilum 

 is divided by irregular concentric refractive fissures into 

 portions of unequal size. This is gelatinized rapidly 

 with much swelling and distortion of the capsule, and 

 the proximal starch, which forms a very finely striated 

 band at the proximal margin, becomes thinner and more 

 refractive and more nearly transparent, until all the 

 material is gelatinized and only the capsule remains. 

 The gelatinized grains are much swollen, have rather 

 thin capsules, and are very much distorted. 



Comparison of the sulphuric-acid reactions between 

 N. albicans and N. empress shows: 



The hilum and lamella? are as distinct as in N. em- 

 press. Gelatinization progresses according to but one 

 method, which is very much like that described for the 

 majority of the grains of N. empress. The points of 

 difference are that the primary starch is divided into 

 granules which are gelatinized somewhat previous to the 

 gelatinization of the secondary starch. The secondary 

 starch is not divided by refractive fissures, but becomes 

 homogeneous-looking and more refractive. The more 

 resistant part of this secondary starch forms a refractive 

 marginal band as the less resistant portion and the pri- 

 mary starch are gelatinized. The marginal band is later 

 gelatinized. The gelatinized grains are as much swollen, 

 do not have thin capsules, and are not so much distorted 

 as in N. empress. 



Narcissus madame de graaff (Hybrid). 



(Plates 13 and 14, figa. 75, 77, and 80; Charts D 317 to D322.) 

 Histologic Properties. 

 In form the grains are much more often simple and 

 isolated than in either parent, in which characteristics 

 it is closer to N. empress and far removed from N. albi- 

 cans, and the aggregates and compound grains seen are 

 of the same types as those of N. empress. There are also 

 a number of grains with well-defined pressure facets on 

 either side of the distal end, indicating that they have 

 existed in aggregates. There are also the same number 



of simple grains in which a primary and a secondary 

 starch formation can be seen. The grains are more 

 irregular in form than in N. albicans and somewhat 

 more irregular than in N. empress, and the irregularities 

 are due to the same causes as described under N. empress. 

 The conspicuous forms more closely resemble those of 

 N. empress and are ovoid, nearly round, broad elliptical, 

 and triangular with rounded angles and base. The addi- 

 tional forms are lenticular, plano-convex, irregularly 

 quadrilateral, clam-shell-shaped, and pyriform. 



In form the grains somewhat more closely resemble 

 N. empress than N. albicans, and some characteristics of 

 N. empress are further accentuated in the hybrid. 



The hilum is not so frequently nor so extensively 

 fissured as in N. empress, nor even as in N. albicans, and 

 the fissures have the following forms: (1) A short, 

 straight or curved line placed horizontally or obliquely ; 

 (2) an irregular Y-shaped figure placed in the transverse 

 axis or obliquely; (3) an X, T, or cruciform figure 

 placed in the transverse and longitudinal axes of the 

 grain ; (4) a flying-bird-like figure. The hilum is some- 

 times centric, but in the majority of the grains is eccentric 

 from 0.45 to 0.29, usually 0.37, of the longitudinal axis. 



In the character and eccentricity of the hilum N. 

 madame de graaff shows a closer relationship to N. 

 albicans than to N. empress. 



The lamella; are usually not distinct, and when they 

 can be seen they are as fine as those of N. albicans and 

 have the same arrangement and characteristics as noted 

 in both parents. The number counted on some of the 

 larger grains varies from 8 to 16, usually 10. 



In the characteristics and number of the lamella? 

 N. madame de graaff is closer to N. albicans than to 2V. 

 empress. 



The grains vary in size from the smaller which are 

 3 by 3/t, to the larger which are 36 by 42/*, rarely, 44 

 by 50/x, in length and breadth. The common sizes are 

 20 by 24fi, 24 by 24/*, and 30 by 24/*. In size N. madame 

 de graaff shows a somewhat closer relationship to N. em- 

 press. The parents and the hybrid do not vary much 

 in size. 



Polariscopic Properties. 



The figure as in N. empress is often not distinct, 

 and is, rarely, well defined. The lines cross at acute 

 angles, which vary widely in size, and they are often 

 bent and bisected, not so frequently as in N. empress, 

 more frequently, however, than in N. albicans. There 

 are as few figures in the form of a conjugate hyperbola, 

 or a long line with bisected ends, as in N. albicans. 



The degree of polarization varies from low to high 

 (value 37), the same as in N. albicans, and there is the 

 same amount of variation in a given aspect of an indi- 

 vidual grain. 



With selenite the quadrants as in N. empress are 

 rarely well defined and are unequal in size, but not so 

 often irregular in shape. The colors are not pure and 

 there are few grains which show a greenish tinge. 



In the degree of polarization, the character of the 

 figure, and the appearance with selenite N. madame de 

 graaff shows a closer relationship to N. empress than to 

 N. albicans. 



Iodine Reactions. 



With 0.25 per cent Lugol's solution the grains are 

 all colored a moderate violet tinged with blue (value 50), 



