630 



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



pointed divisions, forming a serrated edge above the unfis- 

 sured material at the distal margin. Each division is in 

 turn fissured and divided into distinct refractive granules 

 and as gelatinization and swelling proceed the divisions 

 coalesce and form a distinctly granular mass which is 

 very resistant. The deposits at the proximal and distal 

 margins and sides form a homogeneous-looking, refrac- 

 tive band which becomes thinner and more nearly trans- 

 parent as it gelatinizes. The granular mass at the distal 

 end is the last part of the grain to be gelatinized, and this 

 process occurs with much infolding and irregular dis- 

 tention of the capsule at this point. The gelatinized 

 grains are much swollen, have rather thin capsules, and 

 are greatly distorted, particularly at the distal end. 



The reaction with copper nitrate begins immediately. 

 Complete gelatinization occurs in about 87 per cent of the 

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

 in 1 minute, and in 100 per cent of the grains and total 

 starch in 3 minutes. 



The reaction with cupric chloride begins immediately. 

 Complete gelatinization occurs in about 33 per cent of 

 the entire number of grains and 60 per cent of the total 

 starch in 1 minute ; in about 83 per cent of the grains and 

 88 per cent of the total starch in 3 minutes ; and in about 

 97 per cent of the grains and in more than 99 per cent 

 of the total starch in 5 minutes. 



The hilum becomes distinct in all the grains, attended 

 by the formation of a bubble in very few. The lamella? 

 are distinct. In eroded grains gelatinization begins at 

 the distal margin, but in normal grains it begins at the 

 hilum. The hilum swells much more rapidly toward the 

 proximal end than toward the distal; indeed, the small 

 amount of material at the proximal end is gelatinized 

 usually before any of the distal material. Two fissures 

 extend obliquely a short distance from either side of the 

 hilum towards the distal margin. The material in- 

 cluded between them assumes a pitted appearance and is 

 then broken up into irregular-sized pieces. These are 

 partially gelatinized and the remainder are pushed to- 

 gether into a refractive mass, and as the grain swells 

 this mass is divided into pyramidal divisions, so that it 

 forms a serrated border which often extends all around 

 the inner border of the marginal band, except at the 

 proximal end. This border and the marginal band gela- 

 tinize comparatively slowly, with considerable distortion 

 of the capsule. The gelatinized grains are very much 

 swollen, have rather thin capsules, and are greatly dis- 

 torted, especially at the distal end. 



The reaction with barium chloride begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

 about 2 per cent of the entire number of grains and 10 

 per cent of the total starch in 1 minute ; in about 40 per 

 cent of the grains and 90 per cent of the total starch in 

 3 minutes ; in about 80 per cent of the grains and 96 

 per cent of the total starch in 5 minutes; and in about 

 96 per cent of the grains and in more than 99 per cent 

 of the total starch in 15 minutes. 



The reaction with mercuric chloride begins imme- 

 diately. Complete gelatinization occurs in about 20 per 

 cent of the entire number of grains and 43 per cent of 

 the total starch in 30 seconds ; in about 64 per cent of the 

 grains and 89 per cent of the total starch in 1 minute ; 

 and in 100 per cent of the grains and total starch in 3 

 minutes. (Chart D 378.) 



Lilium parbyi (Pollen Parent). 



(Plate 17, fig. 101; Charts D 373 to D 378.) 

 Histologic Properties. 



In form the grains are usually simple and isolated, 

 and compound grains and aggregates are of even less 

 frequent occurrence than in L. pardalinum. The com- 

 pound grains all belong to the same type already de- 

 scribed under L. pardalinum. The aggregates consist of 

 2 small equal-sized grains which are adherent at their 

 distal ends. The grains are somewhat less irregular than 

 in L. pardalinum, and the irregularities are due to the 

 following causes, which are all seen in L. pardalinum, 

 together with one or two other causes : ( 1 ) Small, irregu- 

 lar elevations and depressions in the distal end and mar- 

 gin of the grain; (2) a greater development of one part 

 of the distal end than of the rest; (3) low, rounded pro- 

 tuberances from the sides and, rarely, from the proximal 

 end. The conspicuous forms are ovoid, pyriform, and 

 elongated elliptical with rounded or flattened distal end. 

 The additional forms are clam-shell-shaped, lenticular, 

 nearly round, and triangular with curved base and 

 rounded angles. The grains are not so often flattened 

 at the distal end as in L. pardalinum. The broad forms, 

 as in L. pardalinum, are somewhat flattened and when 

 seen on edge have an ovoid or elliptical shape. 



The hilum when not fissured is a moderately distinct 

 small, round or lenticular-shaped spot. It is not fissured 

 in a majority of the grains as in L. pardalinum, but in 

 a moderate minority. The fissures have the following 

 forms: (1) A single short, straight transverse or slightly 

 oblique line; (2) an irregular stellate arrangement of a 

 number of fissures. The hilum is eccentric from 0.4 to 

 0.06, usually 0.18, of the longitudinal axis, slightly more 

 than in L. pardalinum. 



The lamcllce are as fine but are not so distinct as 

 those of L. pardalinum. There is usually one broad re- 

 fractive lamella, as in that starch, which is continuous 

 and also situated about two-thirds or three-fourths of 

 the distance from the hilum to the distal margin. This 

 separates the fine proximal lamella: from those at the 

 distal end which are not so fine. In other characteristics 

 they are the same as in L. pardalinum. The number 

 counted on the larger grains varies from 20 to 40, usually 

 30, somewhat less than in L. pardalinum. 



In size the grains vary from the smaller which are 

 6 by 5/a, to the larger elongated grains which are 45 by 

 34/a, and the larger broad grains which are 40 by 40/t, 

 in length and breadth. The common sizes are 22 by 

 10/x and 22 by 18/x. The sizes of corresponding types are 

 distinctly less than in L. pardalinum. 



The figure is as distinct and usually somewhat better 

 defined than in L. pardalinum. The lines are not so 

 thick and do not tend to become so diffuse near the mar- 

 gin, and they usually cross at a very acute angle and are 

 more often bent than in that starch. There are but few 

 grains 1 in which a cross-bar is seen connecting the two 

 long arms of the cross. 



The degree of polarization varies from low to high 

 (value 50), less than in L. pardalinum, and there are not 

 so many grains in which it is high. There is also not 

 so much variation in a given aspect of an individual 

 grain. 



