806 



STAKCHES OF CANNACE^. 



The reaction with chromic acid begins in 15 seconds and is over in 2 minutes. It is the same 

 qualitatively as that of the grains of C. warszewiczii. 



With pyrogaUic acid the reaction begins in a minute. About half the grains are gelatinized in 

 10 minutes, and all nearly completely in 30 minutes. The reaction is qualitatively the same as that 

 of the grains of C. warszewiczii. 



Reaction with ferric chloride begins in a few grains in 1 J^^ minutes, most grains are gelatinized 

 in 10 minutes, and all in 22 minutes. The reaction is qualitatively the same as that of the grains of 

 C. warszewiczii. 



The reaction with Purdy's solution begins at once and is over in a minute. It is the same quali- 

 tatively as that of the grains of C. warszeiciczii. 



STARCH OF CANNA VAR. (MRS. KATE GREY). (Plate 85, figs. 505 and 506. Chart 342.) 



Histological Characteristics. — Inform the grains are simple with the exception of a few compounds 

 of two or three components. There are no aggregates, clumps, or pressure facets. The surface is 

 usually fairly regular. Irregularities are due chiefly to small rounded protuberances and nipple- 

 like projections. The conspicuous forms are the narrow to broad flattened ovoid; also quadrangular 

 forms with rounded angles, oval, pyriform, almost round, 

 elliptical, triangular with rounded angles, some approxi- 

 mations to the clam-shell type, and various indefinite 

 forms. The grains are flattened and are about one-fourth 

 to one-half as thick as broad, and commonly about one- 

 half to seven-eighths as broad as long. Seen on edge they 

 are somewhat elliptical and one end is usually narrower 

 than the other. 



The hilum is a fairly distinct, small, round or lenticu- 

 lar spot, usually eccentric from the extreme margin to 

 about one-sixth to one-ninth of the longitudinal axis of 

 the grain and in or near the median line. It is occasion- 

 ally fissured, the fissure being in the form of a very small, 

 shallow, transverse line. There may be 2 or rarely more 

 hila arranged linearly. 



The lamellm are distinct, usually fine, fairly regular 

 circles aroxmd the hilum, or segments of circles beyond, 

 which are probably continuous. They occasionally show 

 waviness and other irregularities, but, as a rule, follow in 

 their form the outline of the distal end. They do not 

 vary greatly in different grains and are generally arranged so that bands of varj-ing numbers of fine 

 lamellae alternate with one coarse, very distinct lamella. In the same grain they are generally not 

 80 fine, but are distinct at the distal end. There are about 65 on the larger grains. 



The grains vary in size from 7 to 68/1. The common size is 40/*. 



Polariscopic Properties. — The figure is very eccentric, distinct, and sometimes clear-cut. The 

 lines are usually broad and not sharply cut. One or two may be seen along the length of the grain. 

 They vary in width and may be bent. If one long line is present it is usually in the longitudinal 

 axis, but if two, they are diagonal. Sometimes the two lines are connected by a third transverse 

 line located about midway between the hilum and the distal end. 



The degree of polarization is very high. It varies somewhat but not greatly in different grains 

 and much in different aspects of the same grain, being highest when the grain is viewed on end or 

 edge. It is not quite so high as in the grains of C. warszewiczii. 



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

 in size. The colors usually are not pure. 



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

 with 0.125 per cent solution they color fairly and the color deepens quickly. The color is deeper 

 than that of the grains of C. warszewiczii. After heating in water until the grains are completely 

 gelatinized, the solution colors fairly deeply and the grains very deeply on the addition of iodine. 

 After lx)iling for 2 minutes the solution colors more deeply and the grain-residues less deeply. The 

 capsules color a violet with excess of iodine. 



Curve of Reaction-Intensities of Starch of Canna var. 

 (Mrs. Kate Grey). 



