GENUS CANNA. 



808 



Qart No. 339. 



grain is sometimes completely surrounded by a secondary system of lamellse. The conspicuous 

 forms are the flattened ovoid; also oval, pyriform, elliptical, nearly spherical, irregularly quadri- 

 lateral and triangular with rounded corners, a few clam-shell type forms, and various irregular 

 forms. The grains are usually much flattened and from one-fourth to one-half as thick as they are 

 broad, and from one-third to three-fourths as broad as long. Seen on edge they are elliptical and 

 may be narrower at one end than at the other. 



The hilum is often invisible on account of its extreme eccentricity. When it can be seen it is 

 a very small, fairly distinct, round spot. It is usually single, but may be multiple, and it is never 

 fissured. It varies in position from the extreme margin to one-sixth to one-ninth of the longitudinal 

 axis, and is in or near the median line. 



The lamellcB are very distinct, fine, fairly regular circles near the hilum, or arcs of circles beyond 

 the hilum which are probably continuous. They are arranged so that groups of fine lamellae 

 alternate with coarse ones. They are not usually so fine and not so distinct at the distal end. 

 They generally follow closely the outline of the distal margin, but are sometimes wavy and irregular. 

 There are from 65 to 70 on the large grains. 



The grains vary in size from 8 to 90fi. The common size is iQfi. 



Polariscopic Properties. — The figure is very eccentric, very distinct, but not usually clear-cut. 

 The lines are generally broad and only one or two are visible throughout their length; their margins 

 are hazy and often somewhat bent and otherwise dis- 

 torted. Two lines are sometimes connected by a third 

 cross-line at about two-thirds the distance from the 

 hilum to the distal end. When one long line is present 

 it is usually in the longitudinal axis, and when there are 

 two lines they are diagonal. 



The degree of polarization is high as a rule. It varies 

 in different grains, in different aspects of the same grain, 

 and in the same aspect of a grain. It is not so high as 

 that of the grains of C. warszemczii. 



With selenite the quadrants are usually fairly well 

 defined, fairly regular in shape, and unequal in size. 

 The colors are not always pure. 



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

 tion the grains color at once a deep violet-blue; with 

 0.125 per cent solution they color fairly and the color 

 deepens rapidly. The color is not so deep as that of the 

 grains of C. warszemczii. After heating in water until 

 the grains are completely gelatinized, the solution colors 

 fairly and the grains deeply on the addition of iodine. 



After boiling for 2 minutes the solution colors deeply and the grain-residues lightly or not at all. 

 With an excess of iodine the capsules become a violet color. Some capsules retain blue-reacting 

 starch in the proximal end. 



Staining Reactions. — With gentian violet and with safranin the grains begin to stain at once 

 and in 30 minutes they 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 gelatinization is 64.5° to 66° C, mean 65.25°. 



Effects of Various Reagents. — With chloral hydrate-iodine reaction begins in 30 seconds and is 

 over in 11 minutes. It is qualitatively the same as that of C. warszewiczii. 



The reaction with chromic add begins in 15 seconds and is over in IJ^ minutes. It is the same 

 quaUtatively as that of the grains of C. warszewiczii. 



Reaction with pyrogallic add begins in a minute and half are fully gelatinized in 10 minutes, 

 about three-fourths are gelatinized in 15 minutes, and all in 40 minutes. The reaction is quaUtatively 

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



With Jerric chloride the reaction begins in a few grains in a minute. Most grains are gelatinized 

 in 7 minutes and all in 18 minutes. The reaction is qualitatively the same as that of the grains of 

 C. warszewiczii. 



Reaction with Purdy's solution begins in a few seconds and is over in Ij^ minutes. It is the 

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



Curve of Reaction-Intensities of Starch of Canna var 

 (Kbnigen Charlotte). 



