GENUS CANNA. 



809 



The degree of polarization is very high. It varies in different grains and in different aspects 

 of the same grain, and somewhat in different parts of the same aspect of a grain. It is the same as 

 that of the grains of C. warszewiczii. 



With selenite the quadrants are usually fairly well defined, fairly regular in shape, and unequal 

 in size. The colors are usually pure. 



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

 with 0.125 per cent solution they color fairly and the color deepens rapidly. The color is slightly 

 deeper than that of the grains of C. warszewiczii. After heating in water until the grains are com- 

 pletely gelatinized, the solution colors fairly and the grains fairly deeply. After boiling for 2 min- 

 utes the solution colors very deeply and the grain-resi- 

 dues lightly or not at all. With an excess of iodine the 

 capsules color a red-violet or violet. Many capsules con- 

 tain blue-reacting starch in the proximal end. 



Staining Reactions. — With gentian violet the grains 

 begin to color at once and in 30 minutes are deeply 

 stained, some more than others. The color is deeper than 

 that of the grains of C. warszewiczii. 



With safranin the grains begin to color at once and in 

 30 minutes are deeply stained, some more than others. The 

 color is the same as that of the grains of C. warszewiczii. 



Temperature Reaction. — The temperature of gelatin- 

 ization is 62° to 63° C, mean 62.5°. 



Effects of Various Reagents. — With chloral hydrate- 

 iodine reaction begins in a minute. It is over in most 

 grains in 7 minutes and in all in 14 minutes. It is the 

 same qualitatively as that of the grains of C. warszewiczii. 



Reaction with chromic acid begins in 15 seconds and 

 is over in 1% minutes. It is the same qualitatively as 

 that of the grains of C. warszewiczii. 



The reaction with pyrogallic acid begins in most grains in 30 seconds. About three-fourths 

 are gelatinized in 6 minutes and practically all in 15 minutes. The reaction is the same qualitatively 

 as that of the grains of C. warszewiczii. 



With ferric chloride the reaction begins in a few grains in 13^ minutes and in almost all in 3 

 minutes; most grains are gelatinized in 12 minutes and all in 20 minutes. The reaction is the same 

 qualitatively as that of the grains of C. warszewiczii. 



The reaction with Purdy's solution begins at once and it is over in 45 seconds. It is the same 

 qualitatively as that of the grains of C. warszewiczii. 



Differentiation of Certain Starches of the Genu^ Canna. 



Histological Chabacteristics. 

 Conspicuous Forms. 

 C. warszewiczii: Usually simple, few compound, no pres- 

 sure facets, some irregularity of surface, flattened; 



broad ovoid and clam-shell type. 

 C. roscoeana: Essentially the same as in C warszewiczii, but 



with less irregularity of surface and apparent absence 



of compound grains, not so well formed clam-shell 



type, and less abundance of irregular forms. 

 C. muscsfolia: Essentially the same as in C. warszewiczii, but 

 less irregular; they resemble more closely Croscoearja. 

 C. edulis: Essentially the same as in C. warszewiczii, but 



with less irregularity, while the most conspicuous 



form is the broad ovoid. 

 C. var. {Konigen Charlotte): Essentially the same as in 



C. warszewiczii, but with less irregularity, while 



the most conspicuous form is the flattened ovoid. 

 C. var. {President Camot): Essentially the same as in 



C. warszewiczii, but the most conspicuous form is 



the flattened, irregular ovoid. 

 C. var. (L. E. Bally): Essentially the same as in C. 



warszewiczii, but less irregular, while the most 



conspicuous form is the flattened ovoid. 



Curve of Reaction-Intensities of Starch of Canna var. 

 (J. D. Eisele). 



Histological Characteristics. — Continued. 

 Conspicuous Forms. — Continued. 



C. var. (Mrs. Kale Grey): Essentially the same as in C 

 warszeiciczii, but the conspicuous form is the nar- 

 row to broad flattened ovoid. 



C. var. {Jean Tissot): Essentially the same as in C. 

 loarszewiczii, but the conspicuous form is the broad 

 ovoid. 



C. var. {J. D. Eisele): Essentially the same as in C. 

 warszewiczii, but the conspicuous form is the 

 broad to flattened ovoid. 



HUum — Form, Number, and Position. 



C. warszewiczii: Form small, distinct, single, round or 

 elliptical, may be multiple; fissuration not com- 

 mon. Position usually very eccentric. 



C. roscoeana: Form small, not very distinct, single round; 

 fissuration not common. Position usually very 

 eccentric. 



C. muscefolia: Form small, very distinct, single, round or 

 lenticular, may be multiple; fissuration uncommon. 

 Position usually very eccentric. 



