GENUS DIEFFENBACHIA. 463 



With sclenite the quadrants are well defined, variable in shape, and very unequal in size. The 

 colors are fairly pure, but less pure than in D. seguine var. nobilis. 



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

 with 0.125 per cent solution they tint readily. In neither reaction is the color as deep as in the 

 grains of D. seguine var. nobilis. After heating the grains until gelatinization has taken place, 

 the solution is colored indigo-blue and all the grains very deeply. The grains are swollen, but 

 retain much of the original form. After boiling for 2 minutes the solution is colored very deeply, 

 but the grain-residues much less deeply. The latter are generally reduced to granular masses. 

 If an excess of iodine is added, these granular masses as well as intact capsules are colored a deep 

 pinkish-violet 



Staining Reactions. — With gentian violet the grains begin to stain at once, staining with equal 

 intensity. After 30 minutes the stain is deep. These grains stain deeper than those of D. seguine 

 var. nobilis. 



With safranin the grains tint slightly in IJ^ minutes and after 30 minutes are deeply stained, 

 more deeply than with gentian violet. There is no difference between the staining reaction of these 

 grains and those of D. seguine var. nobilis. 



Temperature Reaction. — The temperature of gelatinization is 68.5° to 69.5° C, mean 69°. 



Effects of Various Reagents. — With chloral hydrate-iodine the reaction begins in a minute; most 

 are darkened and gelatinized in 20 minutes and all in 40 minutes. The hilum becomes very distinct 

 as a dark spot or bubble. The lamellae remain unchanged in point of distinctness. The margin 

 grows clearer and darker, causing the inner part to appear light and opaque. All of the grains 

 are tinted a light violet. The distal end of the grain becomes dark at the margin and protrusion 

 begins. The smaller grains often darken all over and then swell. Gelatinization advances to the 

 hilum, which swells, and the whole grain is converted into a gelatinous mass. Occasionally gelatin- 

 ization begins at both ends of the grain and advances in all directions. The gelatinized grains 

 then formed are proportionally much elongated, but not much widened; they present strikingly 

 alternate light and dark segments, the dark segments appearing to consist of several rows of lamellae. 

 The proximal end presents a rounded, smooth margin inclosing a clear, light space that represents 

 the swollen hilum. The grains have a dark indigo color; they are not much distorted and largely 

 retain their original shape. 



The grains begin to react with chromic acid in 30 seconds and are dissolved in 4 minutes. The 

 hilum and lamellae become more distinct. Two refractive lines radiate from the hilum, outlining 

 an inner space which becomes so broken up by longitudinal and transverse fissures that it appears 

 granular, the granules sometimes appearing to be arranged in regular rows corresponding to the 

 rows of lamellffi. The margin becomes darker and more distinct, especially at the proximal end, 

 where it is broader than elsewhere and shows fine striations. The hilum may swell and a portion 

 of the margin near it dissolve, followed by the opening out, the extrusion of inner semiliquid 

 starch, and then disappearance with other parts of the grain. The distal end may dissolve first, 

 the proximal end dissolving last; or both ends may dissolve, leaving the central portion, which 

 disappears later, the marginal parts going last. The lower end, if a chloroplastid adhere to it, usu- 

 ally separates and dissolves independently. 



The grains begin to react with pyrogallic acid in a minute and are completely gelatinized in 

 8 minutes. Both hilum and lamellae become very distinct, and two refractive lines extend from the 

 hilum to the distal end of the grain, outhning an inner space. Longitudinal fissures extend in from 

 the distal end and spread out somewhat as they reach upwards, dividing the inner portion into 

 granules. Transverse fissures appear, and others in conjunction with the transverse fissures cause 

 the grain to appear granular, the granules being arranged in rows corresponding to the lamellae. 

 The distal end in the meanwhile spreads out and becomes gelatinous. The hilum now swells enor- 

 mously, and the granules referred to are gelatinized, leaving a finely striated margin which finally 

 clears. The gelatinized grains are very large and more swollen longitudinally than transversely. 

 The proximal end is smooth and rounclcd, and the distal end lobulated and much folded. 



With ferric chloride the grains begin to swell in 2 minutes and all are gelatinized in 15 minutes. 

 Both hilum and lamellae are very distinct. The distal end of the grain becomes divided by 

 fissures i)rojected from the margin to the proximal end. The distal end swells, especiallj' laterally, 

 which swelling may proceed to the hilum, the last part to be gelatinized; or the hilum may swell 

 when only a part of the distal end is gelatinized. The inner portion of the grain is often irregu- 



