554 



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



not as do similar grains of N. princess mary. The gela- 

 tinized grains are much swollen and have as thick cap- 

 sules and are as much distorted as in N. princess mary. 

 In this reaction N. cresset shows qualitatively a closer 

 relationship to N. princess mary than to N. poeiicus 

 poetarum. 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 80 per cent of 

 the entire number of grains and 98 per cent of the total 

 starch in 2 minutes; and about 96 per cent of the grains 

 and 99 per cent of the total starch in 5 minutes. (Chart 

 D 304.) 



The hilum is distinct and a bubble is formed there in 

 the majority of the grains, more often than in either 

 parent, but in this respect more closely resembling N. 

 princess mary. The lamellae are not so often moderately 

 distinct as in either parent. Gelatinization begins at 

 the hilum and progresses according to the two methods 

 described as in general the same under both parents. 

 The methods as a rule are the same as those of N. prin- 

 cess mary, but in some grains they are the same as those 

 of N. poeticus poetarum. The gelatinized grains are as 

 much swollen, have thinner capsules, and are as much 

 distorted as in N. princess mary. 



In this reaction N. cresset shows qualitatively a some- 

 what closer relationship to N. princess mary than to 

 N. poeticus poetarum. 



18. STARCHES OF NABCISSUS ABSCISSUS, N. POETICUS 



POETABUM, AND N. WILL SCABLET. 



Starch of N. poeticus poetarum is described on pp. 

 519 to 522. 



N. ABSCISSUS (SEED PARENT). 



(Plate 12, fig. 67; Charts D 305 to D 310.) 

 HISTOLOGIC PBOPEBTIES. 



In form the grains are usually simple and isolated, 

 but there are moderate numbers of both compound grains 

 and aggregates. The compound grains belong to the 

 following two types, which are placed in the order of 

 their frequency of occurrence: (1) 2, 3, or 4 very small 

 grains, each composed of a hilum and 1 or 2 lamellae, 

 all inclosed in 3 or 4 common secondary lamellae ; (2) 

 3 or 4 hila embedded in an amorphous-appearing mass 

 of starch, the whole surrounded by 1 or 2 secondary 

 lamellae. The aggregates consist of 2, 3, or 4 simple 

 grains arranged linearly or in an irregular pyramidal 

 group. A small majority of the grains show clearly 

 both primary and secondary starch formations. The 

 grains are usually irregular in form and the irregularities 

 are due to the following causes: (1) Small and irregular 

 elevations and depressions in the surface and margin ; (2) 

 small pointed and large rounded protuberances from the 

 margin at various points; (3) irregularly placed pres- 

 sure facets on the sides and distal end ; (4) deviation of 

 the transverse axis, usually near the middle with conse- 

 quent bending of the grain. The conspicuous forms 

 are ovoid, lenticular, plano-convex, irregularly quadri- 

 lateral, and triangular. The additional forms are ellipti- 

 cal, broad reniform, nearly round. The grains are not 

 flattened. 



The hilum, if not fissured, is a distinct round or, 

 rarely, lenticular spot. It is usually very deeply and 

 extensively fissured, and the fissures have the following 



forms: (1) A single straight, horizontal or longitudinal 

 line which is often somewhat branched; (2) cruciate, 

 T,- Y,- or V-shaped; (3) an irregularly stellate group 

 of fissures. The hilum sometimes centric, but in the 

 majority of the grains it is eccentric from 0.43 to 0.3, 

 usually 0.38, of the longitudinal axis. 



The lamellce are moderately distinct, continuous, 

 rather fine rings which are more distinct near the hilum 

 than near the margin. They have in general the form 

 of the outline of the grain, but only near the margin do 

 they follow the contour closely. The number counted on 

 the larger grains varies from 6 to 14, usually 10. 



In size the grains vary from the smaller which are 

 4 by 4/x, to the larger broad forms which are 26 by 40ju,, 

 and, rarely, the larger elongated forms, which are 40 by 

 28/ci, in length and breadth. The common sizes are 20 by 

 24/t, 20 by 28/t, and 24 by 20/t. 



Comparison of the histologic characteristics between 

 N. poeticus poetarum and N. abscissus shows : 



There are not so many aggregates and compound 

 grains as in N. abscissus, and the compound grains be- 

 long to the following types, the first two of which are not 

 seen in N. abscissus: (1) 2 small grains surrounded by 

 4 or 5 secondary lamellae; (2) a large grain to which a 

 small grain has become adherent and both inclosed in 2 

 or 3 common secondary lamellae; (3) a number of hila 

 in an amorphous-looking mass which is surrounded by 

 1 or 2 secondary lamellae. The aggregates rarely con- 

 sist of more than 2 grains, but sometimes 3 grains are 

 seen linearly arranged. The grains are somewhat less 

 irregular, and the irregularities are due to the same 

 causes as in N. abscissus, with the exception of that owing 

 to deviation of the axis of the grain. The simple grains 

 somewhat less frequently show primary and secondary 

 starch formations. There is not much variation in the 

 types of forms in the two starches. 



The hilum when not fissured is as distinct as in 

 N. abscissus, and is not quite so often but somewhat more 

 deeply and more extensively fissured. The fissures more 

 frequently have a cruciate, Y-, or T-shape, but otherwise 

 resemble closely those of the grains of N. abscissus. The 

 degree of eccentricity is the same. 



The lamellce in some grains are more distinct, and 

 are coarse rather than fine as in N. abscissus; they have 

 the same arrangement. 



In size the grains are distinctly larger and have but 

 few forms whose longitudinal axis is much longer than ' 

 the transverse axis. The common sizes are 32 by 30/x, 

 and 30 by 34/t. 



POLARISCOPIC PROPERTIES. 



The figure is usually not very distinct nor well de- 

 fined. The lines cross at angles of widely varying size, 

 and are often bent and sometimes bisected. There are a 

 number of multiple figures and some with 5 or 6 lines 

 instead of 4. The figure has sometimes the form of a 

 conjugate hyperbola, or of a long line bisected at both 

 ends. 



The degree of polarization varies from low to high 

 (value 43) ; there are very few grains in which the degree 

 of polarization is high; commonly it is moderate, and 

 sometimes low. There is usually considerable variation 

 in a given aspect of an individual grain. 



