GENUS AL8TRCEMBRIA. 



661 



Polariscopic Properties.— The figure is generally markedly eccentric, distinct, and as a rule 

 fairly clear-cut. In most grains the lines become wider and less sharply defined as they near the 

 margin, and they may be somewhat bent and otherwise distorted, and often placed at varying 

 angles to one another. Multiple and double figures are rare. 



The degree of polarization is high and does not vary greatly in different grains or in different 

 aspects of the same grain. It is not so high as that of the grains of A. ligtu. 



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

 size. The colors are fairly pm-e. 



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

 with 0.125 per cent solution they color fairly deeply and 

 the color deepens rapidly. The color is deeper than in the 

 grains of A. ligtu. After heating in water until the grains 

 are completely gelatinized, the solution colors fairly deeply 

 and the grains deeply on the addition of iodine. After 

 boiling for 2 minutes the solution colors very deeply, but 

 most of the grain-residues not at all. When an excess of 

 iodine is added the capsules color a pinkish-violet. Very 

 few of the capsules still contain blue-reacting starch, and 

 they are collapsed, broken, and twisted. 



Staining Reactions.— With gentian violet the grains 

 begin to stain at once, and in 30 minutes are very deeply 

 stained, some more than others. They are much more 

 deeply stained than the grains of A. ligtu. 



With safranin the grains begin to stain at once and 

 in 30 minutes are very deeply stained, some more than 

 others. They are more deeply stained than the grains 

 of A. ligtu. 



Temperature Reaction. — The temperature of gelatin- 

 ization is 57° to 58.5° C, mean 57.75°. 



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

 over in 6 minutes. It is qualitatively the same as that of corresponding grains of A. ligtu. 



Reaction with chromic acid begins in a few seconds and is over in 30 seconds. It is qualitatively 

 the same as in corresponding grains of A. ligtu. 



The reaction with pyrogallic add begins in 15 seconds and is over in all but a very few grains in 

 2 minutes. It is qualitatively the same as in corresponding grains of A. ligtu. 



With ferric chloride the reaction begins in a few grains in a minute and is over in all the grains 

 in 14 minutes. It is the same qualitatively as in corresponding grains of A. ligtu. 



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

 the same as in corresponding grains of A. ligtu. 



MINUTES 



Curve of ReactioTi'Intensities of Starch of 

 AUtrcemeria brasiUensis. 



STARCH OF ALSTRCEMERIA AURANTIACA (AUREA). (Plate 57, figs. 341 and 342. Chart 226.) 



Histological Characteristics. — -In form the grains are usually simple, with a few compound 

 grains and aggregates. Single, large pressure facets were observed in a few isolated grains. Some- 

 times a small grain appears to be embedded in a large one. The surface of the grains tends to be 

 quite regular. The conspicuous forms are the ovoid to spherical, and oval. The grains are not 

 flattened, and appear spherical when seen on end. 



The hilum is nearly always fissured, and the fissuration is very deep, wide, ragged, and usually 

 stellate. There may be but one fissure placed obliquely, transversely, or longitudinally, but there 

 are usually two or more large, deep fissures very irregularly arranged; or a great number of fine 

 fissures radiating from the hilum, almost to the margin of the grain. There may be double and mul- 

 tiple hila, linearly arranged, one or all of which may be fissured. If the hilum is not fissured it is a 

 somewhat indistinct, rather large round spot. It is usually eccentric about two-fifths to one-third 

 of the longitudinal axis of the grain, and in the median line. 



The lamellcB are fairly distinct, rather coarse, regular rings which, except those near the hilimi, 

 tend to follow the outline of the margin of the grain. They are usually continuoiis ellipses, but 



