GENUS TRILLIUM. 



619 



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

 with 0.125 per cent solution they color fairly deeply, and the color deepens rapidly. After heating 

 in water until the grains are completely gelatinized, the solution colors fairly deeply and the grains 

 deeply on the addition of iodine. After boiling for 2 minutes the solution colors very deeply and 

 the grain-residues lightly or not at all. With an excess of iodine the capsules color a light violet 

 and some retain some blue-reacting starch. 



Staining Reactions. — With gentian violet and with safranin the grains begin to stain very lightly 

 in a minute and in 30 minutes they are still very lightly colored. 



Temperature Reaction. — The temperature of gelatinization is 57° to 59° C, mean 58°. 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins at once and is over 

 in nearly all in 45 seconds. The margin at the two ends becomes dark and swells slightly, and the 

 reaction spreads rapidly from both points into the in- 

 terior until the hilum is reached. The hilum swells very 

 rapidly and the rest of the grain also swells consider- 

 ably. A bubble can often be seen to form at the hilum, 

 first increasing and then decreasing in size, and finally 

 disappearing. The gelatinized grains are of a uniform 

 dark color, usually fairly large, and retain some of the 

 original form. 



Reaction with chromic acid begins at once and is over 

 in 14 seconds. It is so rapid that it is impossible to dis- 

 tinguish the steps. 



The reaction with pyrogallic add begins at once and 

 is over in 45 seconds. The hilum swells and a bubble 

 appears at this point, which first increases and then de- 

 creases in size and finally disappears. The inner portion 

 of the grain passes rapidly into a gelatinous mass and the 

 whole grain swells. The marginal starch forms a thin, 

 transparent capsule, which grows thinner as the grain con- 

 tinues to swell. The gelatinized grains are large, wrinkled, 

 and folded, and do not retain any of their original form. 



Reaction with ferric chloride begins in many grains in 15 seconds and is over in 5 minutes. 

 Internal fissuration occurs at one or two points, and from these fissures gelatinized material pro- 

 trudes beneath the capsule, and forces out the capsule. This process often extends all around the 

 margin and then inward over the interior of the grain, and when the part of the grain immediately 

 surrounding the hilum is reached a large fissure extends inwardly, giving rise to division of the 

 intracapsular part of the grain into two parts, which in turn may be divided and subdivided. The 

 pieces thus formed become separated by wide spaces of gelatinized starch, and are then gelatinized 

 independently of one another. The gelatinized grains are large, irregular, folded, and variously 

 distorted, and do not retain any of the original form of the grain. 



Reaction with Purdy's solution begins at once and is over in 10 seconds. It is so rapid that it is im- 

 possible to detect the separate steps, but it is in all probability the same as that with pyrogallic acid. 



STARCH OF TRILLIUM OVATUM. (Plate 50, fig. 299. Chart 203.) 



Histological Characteristics. — In form the grains are simple and isolated, with the exception of a 

 very few small aggregates and clumps which are readily separated. No pressure facets were observed. 

 The surface is usually smooth, but somewhat irregular, owing to irregularities in growth. The 

 conspicuous forms are the oval to ovoid, and round. In addition there are elliptical, pyriform, 

 reniform, lenticular, and irregular shapes. Some grains are two-thirds as thick as they are wide, 

 and nearly all are less thick than broad. The lenticular grains are relatively much more abundant 

 in this starch than in either of the others. 



The hilum usually is not distinct, but when it can be seen it appears as a large round or len- 

 ticular spot, usually eccentric about two-fifths or less of the longitudinal axis, and in or slightly to 

 one side of the median line. It is rarely fissured. 



The lamella are invisible. 



The grains vary in size from 1.5 to 10/ii. The common size is 7/i. 



Curve of Reaction-Intensities of Starch of Trillium 

 grandiflorum. 



