OENVS TRITONIA (MONTBRETIA). 



733 



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

 are generally broad and not clearly defined, and may be bent or otherwise distorted. 



The degree of polarization is fairly high. It varies greatly in different grains and in different 

 parts of the same aspect of a given grain. 



With selenite the quadrants are fairly well defined, and tend to be irregular in shape and un- 

 equal in size. The colors are fairly pure. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color lightly a violet tinged 

 with blue and the color deepens fairly rapidly; with 0.125 per cent solution they color very lightly 

 and the color deepens slowly. The color is less than in T. crocata. After heating in water until 

 the grains are gelatinized, the solution colors fairly and the grains deeply. After boiling for 2 minutes 

 the solution colors deeply and the grain-residues fairly. The capsules color violet with a slight 

 excess of iodine and most of them retain some blue-reacting starch. 



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

 and in 30 minutes are fairly stained. The color is deeper than in T. crocata. 



Temperature Reaction. — The temperature of gelatinization is 72° to 73° C, mean 72.5". 



Effects of Various Reagents. — With chloral hydrate-iodine the reaction begins in many grains in 

 a minute; about half are gelatinized in 12 minutes, two-thirds in 22 minutes, four-fifths in 35 minutes, 

 and almost all in 1 J^ hours. The reaction is qualitatively the same as that of the grains of T. crocata. 



Reaction with chromic add begins in 30 seconds and is over in 4 minutes. It is qualitatively 

 the same as that of the grains of T. crocata. 



The reaction with pyrogallic add begins in 45 seconds and is over in 12 minutes. It is the same 

 qualitatively as that of the grains of T. crocata. 



The reaction with ferric chloride begins in some grains in IJ^ minutes. About two-thirds are 

 gelatinized in 11 minutes, almost all in 20 minutes, and all in 37 minutes. The reaction is the same 

 qualitatively as that of the grains of T. crocata. 



The reaction with Purdy's solution begins slightly in a few grains in 13^ minutes, all show some 

 reaction and a few are partially gelatinized in 30 minutes, and all are partially and a few nearly 

 completely gelatinized in IJ^ hours. The reaction is qualitatively the same as that of the grains 

 of T. crocata. 



P I GV T P_ 



aart No. 284. 



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

 POPS 



5 I 



STARCH OF TRITONIA CROCOSM^FLORA. (Plate 72, figs. 431 and 432. Chart 284.) 



Histological Characteristics. — In form the grains are simple and are isolated, except a few aggre- 

 gates of two or more components. Most of the larger grains are marked by one or two, sometimes 

 three or more, pressure facets; there are some clumps. 

 The surface of the grains is rounded and tends to be 

 quite regular. The conspicuous forms are hemispherical 

 and spherical to oval, with some triangular and other 

 polygonal forms, which vary in shape in accordance 

 with the number, size, and arrangement of the pressure 

 facets. The grains are not flattened and appear spher- 

 ical on end. Their general appearance is like those of 

 T. pottsii, but like the latter differs materially from those 

 of the other tritonias. 



The hilum is a distinct, small, round spot, usually 

 eccentric about two-fifths of the longitudinal axis and in 

 the median line. It is often fissured, and there is usually 

 a single shallow, short, straight or curved fissure, usually 

 transverse, sometimes diagonal or longitudinal. There is 

 sometimes an irregularly stellate arrangement of short 

 fissures. Rarely there are double hila. 



The lamellce are not as a rule distinct. They ap- 

 pear to be continuous, regular, rather coarse rings which 

 usually follow the outline of the margin. They do not 



vary much in size and distinctness in different grains, but are usually coarser and more distinct 

 near the hilum than near the margin. There are 8 to 10 on the larger grains. 



The grains vary in dze from 2 to Mn. The common size is 20^. 



Curve of Reaction-Intenaitie* of Starch of Tntonia 

 crocotmaeflora. 



