834 



STARCHES OF MARANTACE^. 



one, sometimes 2 or more, distinct, refractive lamellte at about half the distance between the hilum 

 and the distal mai'gin of the grain. The number of lamellce is about 12 to IG on the larger grains. 



The size of the smallest grains is 6 by 6ju; the large are 24 by 12ju to 18 by 12/i in length and 

 breadth; the common size is about 18;u. 



Polariscopic Properties. The figure is eccentric and fairly clear-cut and generally regular. 

 Its lines are usually straight and rather thin, but occasionally they are bent and they may be at 

 various angles to one another. 



The degree of polarization is fair. It varies in different grains and somewhat in the same aspect 

 of a grain. It is not so high as M. arundinacea var. (Commercial No. 1). 



With selcnite the quadrants are fairly well defined, irregular in shape, and unequal in size. 

 The colors are fairly pure. 



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

 with blue; with 0.125 per cent solution they color lightly and the color deepens somewhat. The 

 coloration is not quite so deep as that of the grains of M. arundinacea var. (Commercial No. 1). 

 After heating in water until the grains are completely gel- 

 atinized, the solution colors lightly and the gelatinized 

 grains very deeply on the addition of iodine. After boil- 

 ing for 2 minutes the solution colors fairly deeply and 

 the grain-residues fairly. The capsules become of a violet 

 color when an excess of iodine is added. 



Staining Reactions. With gentian violet and with saf- 

 ranin the grains begin to stain at once and in 30 minutes 

 they are very lightly stained, one as much as another. 

 The color is very much less than that of the grains of M. 

 arundinacea (Commercial No. 1). 



Temperature Reaction. The temperature of gelatin- 

 ization is 85 to 86 C, mean 85.5. 



Effects of Various Reagents. With chloral hydrate- 

 iodine the reaction begins in all the grains in 30 seconds; 

 nearly all are gelatinized in 5 minutes and all in 7 min- 

 utes. It is the same qualitatively as that of the grains of 

 M. arundinacea V ax. (Commercial No. 1), but all the mar- 

 ginal starch usually becomes gelatinized before that of 

 the interior of the grain. 



Reaction with chromic acid begins in some grains in 15 seconds and in all in 30 seconds and is 

 over in 6 minutes. It is the same qualitatively as that of the grains of M. arundinacea var. (Com- 

 mercial No. 1). 



The reaction with pyrogallic acid begins in some grains in 13^^ minutes. All are partially gelat- 

 inized in 15 minutes and about half are completely gelatinized in 22 minutes. The reaction is 

 qualitatively the same as that of the grains of M. arundinacea var. (Commercial No. 1). 



Reaction with ferric chloride begins in some grains in a minute; almost all are partially gelat- 

 inized in 22 minutes; half are completely gelatinized in 1^ hours, nearly all in 2 hours, and all in 

 2^ hours. The reaction is the same qualitatively as that of the grains of M. arundinacea var. 

 (Commercial No. 1). 



The reaction with Purdy's solution begins in some gi-ains in 45 seconds, and in 7 minutes one- 

 third are partially gelatinized. The reaction is the same qualitatively as in M. arundinacea var. 

 (Commercial No. 1). 



STARCH OF CALATHEA VANDENHECKEI. (Plate 91, figs. 541 and 542. Chart 354.) 



Histological Characteristics. In form the grains are usually simple, with a few compounds and 

 a few small aggregates usually in the form of one very large grain with one very minute grain. Pres- 

 sure facets are occasionally found; clumps are rare. The surface of the grains is often somewhat 

 irregular, owing chiefly to lateral protuberances, or nipple-like projections, or to indentations, 

 usually of the distal end. The conspicuous forms are oval, ovoid, roimded triangular, and oyster-, 

 mussel-, and clam-shell-shaped; also some elliptical, spherical, and nearly spherical forms. In a few 

 grains the transverse diameter is larger than the longitudinal. 



Curve of Reaction-Intcnsities of Starch of Calathea 

 wiotiana. 



