746 



STARCHES OF IBIDACB^. 



I GV 



s 



PS CI PA I 

 PC PS 



than those of C. siisianus (Cloth-of-Gold) ; the aggregates are of similar character to those of C. 

 tusianus (Cloth-of-Gold), but the proportion of doublets and triplets is much greater. 



The hilum is frequently observed as a round or lenticular spot, usually centric or from slightly 

 to one-third eccentric of the longitudinal axis. The fissures and cavity found sometimes at the hilum 

 are similar to those noted for C. susianus (Cloth-of-Gold) and the hilum is more often demonstrable, 

 and when present the fissures or cavities are deeper. 



The lameUoe are not usually demonstrable. Occasionally they can be observed, and they gen- 

 erally appear as complete rings near the hilum, but tend to follow the outline of the margin through- 

 out the greater part of the grain. In the dome-shaped grains the lamellse near the hilum also usually 

 have the form of the margin of the grain. One coarse and refractive lamella is often found at vary- 

 ing distances between the hilum and the distal end. In round forms this lamella is usually at the 

 equator. On grains of fair size, 8 to 10 lamellse can 

 occasionally be counted. Chart No. 290. 



The grains vary in size; the smaller ones are 3 by 

 2p; the larger are 24 by 23;i in length and breadth; the 

 common size is 16 by 14^4 in length and breadth. A 

 number of round grains may reach the size of 20/i. The 

 common size is 12;t. 



Polariscopic Properties. — The figure is centric or 

 slightly eccentric. It is of similar character to that 

 noted for C. susiamts (Cloth-of-Gold), but is more often 

 regular and distinct throughout the entire grain. Double 

 or multiple figures are also observed. 



The degree of polarization is fair to high. There is 

 a greater variation in the different grains than in C. 

 susiamis (Cloth-of-Gold), and the proportion of grains 

 in which the polarization is high is much greater. The 

 same variation in one aspect of a given grain is observed, 

 but such grains are less often found than in C. susianus 

 (Cloth-of-Gold). 



With selenite the quadrants are frequently well de- 

 fined. They are clean-cut in a much greater proportion of grains than in C. susianus (Cloth-of- 

 Gold). The quadrants are usually somewhat irregular in shape and unequal in size; but there are 

 more grains in which they are regular and equal than in C. susianus (Cloth-of-Gold). The same 

 degree of piu-ity of the colors and variation in the different quadrants is observed as that noted for 

 C. susianus (Cloth-of-Gold), but the colors are pure in a greater proportion of the grains. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color a fairly deep violet 

 with a reddish tint, which becomes quite deep in 2 minutes; with 0.125 per cent solution the grains 

 color a very light reddish violet, some deeper than others, which becomes fairly deep in 2 minutes. 

 The grains are slightly redder in tint, color more unevenly, and deepen in tint more slowly than in 

 C. suManu^ (Cloth-of-Gold). After heating in water until the grains are gelatinized, the solution 

 colors a deep indigo-blue and the grains from a light indigo-blue to quite a light blue with a reddish 

 tint on the addition of iodine. The solution is deeper in color and the grains lighter and some not 

 so pure a blue as in C. svmanv^ (Cloth-of-Gold). If the grains are boiled for 2 minutes and then 

 treated with iodine the grain-residues color a light blue-violet to rather deep indigo-blue and the 

 solution very deep blue. There is a greater range of tint in the gelatinized grains and the solution 

 is deeper than in C. susianus (Cloth-of-Gold). With an excess of iodine the grain-residues color a 

 lighter yet quite deep purple, and the capsules a lighter heliotrope to a wine-red. 



Staining Reactions. — With gentian violet when viewed in masses the grains show a slight trace of 

 color at once and in 30 minutes are lightly colored, about the same as in C. susianus (Cloth-of-Gold). 



With safranin the grains color very slightly immediately and in 30 minutes are lightly to fairly 

 stained. The color is about the same as in C. susianus (Cloth-of-Gold). 



Temperature Reaction. — The temperature of gelatinization is 75° to 76°C., mean 75.5°. 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins at once. A few grains 

 are gelatinized in a minute, the majority in 5 minutes, and all but rare resistant grains in 7 minutes. 

 The reaction is complete in the latter in 12 to 17 minutes. The larger round grains and others with 



Curve of Reaction-Intensities of Starch of Crocus 

 versicolor (Cloth-of-Silver). 



