GENUS CANNA. 



807 



P I GV I P 



s 



Chart No. 343,. 



GV S T CI CA PA FC P S CI PA CA 

 — PC PS 



S I 



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

 and in 30 minutes are fairly deeply stained, some more than others. The color is not so deep as 

 that of the grains of C. warszewiczii. 



Temperature Reaction. — The temperature of gelatinization is 62° to 63° C, mean 62.5°. 



Effects of Various Reagents. — With chloral hydrate-dodine reaction begins in a minute and is 

 over in 13 minutes. It is qualitatively the same as that of the grains of C. warszewiczii, except 

 that the grains are colored a much deeper violet at the beginning of the reaction. 



Reaction with chromic acid begins in a very few seconds and is over in IJ^ minutes. It is 

 qualitatively about the same as that of the grains of C. warszewiczii, the main point of differ- 

 ence being that with these grains a serial separation of crescents from the distal end does not 

 often occur. 



With pyrogallic acid the reaction begins in 30 seconds. Nearly all are completely gelatinized 

 in 10 minutes and all are fully gelatinized in 20 minutes. The reaction is the same qualitatively 

 as that of the grains of C. warszewiczii. 



The reaction with /erne chloride begins in some grains in a minute and in nearly all in 2 minutes. 

 Almost all are gelatinized in 10 minutes and all in 16 minutes. The reaction is qualitatively the 

 same as that of the grains of C. warszewiczii. 



Reaction with Purdy's solution begins at once and is over in 30 seconds. It is qualitatively 

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



STARCH OF CANNA VAR. (JEAN TISSOT). (Plate 85, figs. 507 and 508. Chart 343.) 



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

 grains consisting of two components. There are no aggregates, few clumps, and no pressure facets. 

 The surface of the grains is fairly regular. In these, as in other Canna grains, small, rounded pro- 

 tuberances and nipple-like projections render the margin 

 of some grains irregular. The conspicuous forms are the 

 broad ovoid, also flattened ovoid, flattened elliptical, len- 

 ticular, oval, pyriform, triangular and quadrilateral with 

 rounded angles, clam-shell type, and various irregular 

 forms. The grains are all flattened so that they are 

 about one-fourth as thick as they are broad, and on end 

 or edge appear as thin flattened ellipses. They range 

 from about half to as broad as long. 



The hilum is often invisible owing to its extreme mar- 

 ginal location. When visible it is a distinct, small, round, 

 or rarely lenticular spot. It is usually eccentric from the 

 extreme margin to about one-sixth to one-ninth of the 

 longitudinal axis, and in or near the median line. It is 

 rarely double and rarely fissured. If a fissure is present 

 it is a very small, single, transverse or diagonal line. 



The lamellce are very distinct, fine, fairly regular cir- 

 cles around the hilum, or segments of circles beyond, 

 which are probably continuous. They usually follow the 

 outline of the distal margin, but occasionally show an 

 irregular waviness not in accordance with the outline of the grain. Those nearer the distal end are 

 often not so fine, though not more distinct, than those near the hilum, and are coarser and more 

 distinct in one grain than in another. There are about 60 lamellae on the larger grains. 



The grains vary in size from 5 to QO/x. The common size is 40^. 



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

 lines are broad, and usuaUy one or two are visible throughout the length of the grain. If there is 

 one such Une, it is in or close to the longitudinal axis, but if two Unes they are diagonally placed. 

 The lines are sometimes connected by a transverse line at about half the distance between the hilum 

 and distal end, and also often vary in width or are bent. 



The degree of polarization is high. It is variable in different grains, being comparatively low 

 in some grains to very high in others. It also varies in different aspects of the same grain and in 

 different parts of the same aspect of a grain. It is not so high as that of the grains of C. warszewiczii. 



53 



Curve of Reaction-Intensities of Starch of Canna var. 

 (Jean Tissot). 



