GENUS SECALE. 



369 



P I GV T P 



Chart No. 17. 



GV S T CI Cft PA FC P S CI PA C 



grains are round, oval, and ovoid. In addition, there arc occasional bean-shaped, slightly poly- 

 gonal, triangular with rounded angles, and hemispherical grains. When viewed on edge the grains 

 are elUiitical, spindle-shaped, or lenticular. The conspicuous forms of the small grains are globular 

 to oval, but since so many of them were jiarts of aggregates they vary cousideraijjy in shape and tend 

 to have angular and somewhat irregular forms, such as triangular, i)oIygoual, dome-shaped, and 

 spintlle-shaped. The grains of Secnle closely resemble those of Triticum, but the largest grains are 

 of greater size, and the small gi-ains teiid to be more angular and variable in shape. 



The hilum is not usually visible. It is rarely observed as a small, clear, round spot which is 

 centric in position. Either an irregular cavity or clefts are often found at the position of the hilum, 

 and the clefts are clean-cut and arrangetl so as to form a cross, a star, or a Y-shaped figure. When 

 viewed on edge, a mesial line or groove similar to that noted under Triticum may be present. The 

 grains of Secale differ from those of Triticum in having the central clefts, but in general the resem- 

 blance is well marked. 



The lamellw are usually indistinct, but occasionally fine, concentric, regular rings can be ob- 

 served, the number of which on large grains is from 12 to 16. 



The gi-ains vary in size from the smaller, which are 2 bj- 2/(, to the larger, which are 48 by 44/^ 

 and 44 by 44u. The common size is 2S/i. 



Polariscopic Properties. The figure is usually centric. It usually is distinct in the medium and 

 small grains, but not in the larger grains. The lines in case of a distinct figure are generally rather 

 thick and straight, broadening towai-ds the margin of the grain. In the indistinct figure of the 

 large grains the lines are diffused and more clearly defined 

 at the margin of the grain. A large central dark space 

 is frequently ob.served. The lines are sometimes either 

 bent or bisected. 



The degree of polarization is low to fairly high when 

 the grains are viewed on the flat, and quite liigh when 

 viewed on edge. It is lowest in the largo grains, and 

 often varies in the aspect of a grain, being higher at the 

 margin than at the center of the large grain. Polariza- 

 tion is higher in a larger proportion of grains than in 

 Triticum. On the whole it is low. 



With sdeiiite the quatlrants are not well defined, are 

 slightly irregular in shape, and unequal in size in most 

 of the grains. In a few grains they are regular in shape 

 and equal in size. The colors in most of the grains are 

 not quite pure. 



Iodine Reactions. With a 0.25 per cent Lugol's solu- 

 tion the grains all color a fairly deep blue to reddish- 

 violet; with a 0.125 per cent solution they color lightly, 

 and the color deepens fairly rapidly. After heating in 

 water until all the gi-ains are completely gelatinized the solution colors fairly antl the gelatinized 

 grains very deeply on the atldition of iodine. After boiling for 2 minutes the solution colors very 

 deeply and most of the gelatinized grain-residues very lightly. The capsules, which are much 

 folded and crumpled, all color red-violet with an excess of iodine. 



Staining Reactions. With gentian violet the gi-ains begin to stain lightly at once, and in 30 

 minutes they are very lightly to lightly stained. 



With safranin the gi-ains begin to stain lightly at once, and in 30 minutes they are very lightly 

 to lightly stained. 



Temperature Reaction. The temperature of gelatim"zation is 60 to 62 C, mean 01. 



Effects of Various Reagents. With chloral hydrate-iodine the reaction begins in most of the 

 grains at once. About half .are gelatinized in 5 minutes, nearly all in 10 minutes, and all in 20 

 minutes. The reaction starts at one or more points on the margin, or on the margin generally, 

 and the process moves inward from all parts, and as a rule more rajiidly from certain are:is. The 

 gelatinized grains are not very large and retain much of their original form. 



The reaction with chromic acid lu'gins in from 10 to 20 seconds and is over in 2M minutes. 

 The hilum and lamelhe sometimes become more distinct, and in some grains the starch at one or 

 two points on the margin, wiiere erosion or gclatinization has i)robably started, begins to gelatinize 



Curve of Reaction-Intensities of Starch of Secale cereale 



var. (Mammoth Winter). 



