586 



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



The hilum becomes distinct, unattended by the for- 

 mation of a bubble in any of the grains. The lamellae 

 become moderately distinct, and evidence of a lamellar 

 structure is visible in some parts of the grain during 

 the greater part of the reaction. Gelatinization begins 

 at the hilum and progresses according to two methods. 

 In the first, which is seen in a small majority of the 

 grains, 2 furrows, or in many cases fissures, extend 

 transversely or obliquely from either side of the hilum to 

 the margin, and the material distal to them and to the 

 hilum loses its structural appearance and becomes a mass 

 of fine granules which is sometimes divided by irregular 

 longitudinal fissures. This granular starch slowly gela- 

 tinizes. In the meanwhile the proximal material is finely 

 striated and as the distal portion swells it forms a 

 finely striated, refractive band at the proximal margin 

 which slowly grows thinner, but which in many grains 

 is never completely gelatinized. In the second method, 

 which is seen in a large minority of the grains, the 

 primary starch immediately surrounding the hilum is 

 divided into three or four portions, which, as the grain 

 swells, are usually subdivided into many particles and 

 widely scattered. The secondary which surrounds the 

 primary material is covered by fine striae and slowly 

 gelatinizes, the more resistant portion forming a finely 

 striated and lamellated band at the margin, around the 

 inner border of which the particles of the primary starch 

 are scattered. Gelatinization in many grains does not 

 advance much further, but in some grains the primary 

 starch granules disappear and the secondary marginal 

 band slowly becomes thinner and more nearly transparent 

 and is finally gelatinized. The gelatinized grains are 

 much swollen, have rather thick capsules, and are con- 

 siderably distorted. 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in about 0.5 per cent of 

 the entire number of grains and 10 per cent of the 

 total starch in 5 minutes; in about 10 per cent of the 

 grains and 29 per cent of the total starch in 15 minutes; 

 in about 13 per cent of the grains and 39 per cent of the 

 total starch in 30 minutes; in about 19 per cent of the 

 grains and 49 per cent of the total starch in 45 minutes; 

 and in about 29 per cent of the grains and 56 per cent 

 of the total starch in 60 minutes. (Chart D 339.) 



The hilum becomes distinct, unattended by the for- 

 mation of a bubble in any of the grains. The lamella? 

 are moderately distinct and evidence of a lamellar struc- 

 ture remains visible during the greater part of the reac- 

 tion. Gelatinization begins at the hilum and progresses 

 according to two methods. In the method which is seen 

 in a small majority of the grains 2 furrows, or in some 

 cases fissures, extend transversely or rarely obliquely 

 from either side of the hilum to the margin and the 

 material distal to them and to the hila loses its struc- 

 tural appearance and becomes a finely granular mass 

 which is much cracked and fissured at the margin. The 

 more resistant starch at the proximal end is coarsely 

 striated, and as the grain swells with the gelatinization 

 of the distal starch, it is pushed to the proximal margin, 

 where it forms a granular band. These granules are 

 gradually gelatinized, leaving only a rather thick cap- 

 sule. In the second method, which is seen in a large 

 majority of the grains, the primary starch immediately 

 surrounding the hilum is divided by fissures into three 



or four portions, which, as the rest of the grain swells, 

 are usually subdivided and scattered, but in a few grains 

 remain clumped together in the center of the grain. The 

 secondary deposit is divided by very distinct, coarse 

 striae into rows of granules according to the arrangement 

 of the lamellae. The less resistant material of the grain 

 is now gelatinized, and the more resistant portion is 

 pushed to the margin, where it forms a marginal band 

 made up of 2 or 3 rows of granules, just inside the inner 

 row of which are the scattered particles of the primary 

 starch which are very resistant and often remain un- 

 gelatinized after the rest of the grain is gelatinized. The 

 rows of granules constituting the marginal band are 

 gelatinized from within outward, the outer row remain- 

 ing visible for a long time. The gelatinized grains are 

 much swollen, have rather thick capsules, and are con- 

 siderably distorted. 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 75 per cent of 

 the entire number of grains and 93 per cent of the total 

 starch in 2 minutes, and in about 97 per cent of the 

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

 (Chart D 340.) 



The hilum becomes distinct, accompanied by the 

 formation of a bubble in a large majority of the grains. 

 The lamellae at first are not distinct, but later become 

 distinct and are then quickly obscured. Gelatinization 

 begins in the interior of the grain and proceeds accord- 

 ing to two methods. In the first method, which is seen 

 in a rather small majority of the grains, 2 furrows or 

 actual fissures extend transversely or obliquely from the 

 hilum on either side to the margin, and the material 

 distal to these furrows and to the hilum becomes dis- 

 tinctly refractive, then the lamellae are separated from 

 one another by refractive fissures, and the whole mass of 

 starch is rapidly gelatinized with much swelling and 

 considerable distortion of the capsule. The proximal 

 portion meanwhile remains unaffected, and as the distal 

 material swells it forms a thick, homogeneous-looking 

 band at the proximal margin, which is later compara- 

 tively slowly gelatinized. In the second method, which 

 is seen in a large minority of the grains, the material 

 immediately surrounding the hilum, which is a primary 

 starch formation, becomes granular in appearance and 

 is broken up into three or four portions by the swelling 

 of the bubbles at the hilum ; meanwhile the lamellae of 

 the secondary starch surrounding the primary deposit are 

 separated from one another by concentric, refractive fis- 

 sures. Following this the whole grain is rapidly gela- 

 tinized, the secondary starch swelling with great rapidity 

 and the granular portions of the primary starch being 

 widely separated and gelatinizing less rapidly. The 

 gelatinized grains are much swollen, have rather thin 

 capsules, and are much distorted. 



NARCISSUS TRIANDRUS ALBUS (POLLEN PARENT). 



(Plates 14 and 15, figs. 83 and 86; Charts D 335 to D 340.) 

 HISTOLOGIC PROPERTIES. 



In form a small majority of the grains are simple 

 and most of the grains are isolated. A large minority are 

 compound and there are a few aggregates. The com- 

 pound grains belong to the following two types : 

 ( 1 ) From 2 to 7 rather small grains, each consisting of a 

 hilum surrounded by 2 or 3 lamella: and all inclosed in 6 



