GENUS HIPPEASTRUM. 



631 



The lines are sometimes bent and other- 

 Chart No. 210. 



I GV 



s 



PS CI PA 

 PC PS 



The grains vary in size from 6 to iOfi. The common size is 22/z. 



Polariscopic Properties. ^The figure is usually eccentric, distinct, sometimes clear-cut, and 

 irregular. Its lines are generally thick, and broader and not so well defined in some parts of their 

 length as in others, especially near the margin of the grain, 

 wise distorted, and often placed at varying angles to one 

 another. Double figures are occasionally observed. 



The degree of polarization is high. It varies in dif- 

 ferent grains, in different aspects of the same grain, and 

 in different parts of the same aspect of a given grain. It 

 is not so high as that of the grains of H. vittatum. 



With selenite the quadrants are, as a rule, not well 

 defined, and are irregular in shape and unequal in size. 

 The colors are usually not quite pure. 



Iodine Reactions. With 0.25 per cent Lugol's solu- 

 tion the grains color a very deep indigo, and with 0.125 

 per cent solution they color fairly and the color deepens 

 rapidly. It is not quite so deep as that of the grains of 

 H. vittatum. After heating in water until all the grains are 

 completely gelatinized, the solution colors fairly and the 

 grains deeply on the addition of iodine. After boiling for 

 2 minutes the solution colors deeply and most of the grain- 

 residues not at all. With an excess of iodine the capsules 

 color a red-violet; some of them are disintegrated. 



Staining Reactions. With gentian violet the grains 

 begin to stain very slightly at once and in 30 minutes are colored fairly deeply, more than the grains 

 of H. vittatum. 



With safranin the grains begin to stain at once and in 30 minutes are fairly deeply stained, 

 deeper than the grains of H. vittatum. 



Temperature Reaction. The temperature of gelatinization is 71.5 to 72 C, mean 71.75. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins in most grains in 1}/^ 

 minutes. About half are gelatinized in 12 minutes, three-fourths in 27 minutes, and almost all in 

 50 minutes. The reaction is the same qualitatively as that of the grains of H. vittatum. 



Reaction with chromic acid begins in some grains in 30 seconds, in all in IJ^ minutes, and is 

 over in 5}^ minutes. It is the same qualitatively as that of the grains of H. vittatum. 



The reaction with pyrogallic acid begins in all the grains in a minute. Almost all are completely 

 gelatinized in 12 minutes and all in 17 minutes. The reaction is qualitatively the same as that of 

 the grains of H. vittatum. 



The reaction with ferric chloride begins in a few grains in IJ^ minutes. About four-fifths are 

 gelatinized in 12 minutes, almost all in 25 minutes, and all in 37 minutes. The reaction is qualita- 

 tively the same as that of the grains of H. vittatum. 



Reaction with Purdy's solution begins in many grains in 2 minutes. About one-fourth are 

 partially and a few completely gelatinized in 20 minutes. About one-third are gelatinized in 30 

 minutes and one-half in an hour. The reaction is the same qualitatively as that of the grains of 

 H. vittatum. 



MINUTES 



Curve of Reaction-IntenBities of Starch of Hippeastrum 

 aulicum var. robustum. 



Differentiation of Certain Starches of the Genus Hippeastrum. 



Histological Characteristics. 

 Conspicuous Forms. 



H. vittatum: Usually simple; some compounds and doub- 

 lets; surface somewhat iiTegular owing chiefly to 

 secondary lamella: and nipple-like processes. 

 Spherical-ovoid, ovoid with pointed distal end, 

 triangular, quadrangular, and polygonal with 

 rounded corners. 



//. equeslrc: Essentially the same as in H. vittatum, ex- 

 cepting comparative rareness of secondary deposi- 

 tions and nipple-like processes. 



H. aulicum var. robustum: Essentially the same as in H. 

 vittatum. 

 42 



HisTOLoaicAL Characteristics. Continued. 



Hilum Form, Number, and Position. 



H. vittatum: Form distinct, fairly large, round or rarely 



lenticular; single or multiple; sometimes fis.sured, 



fissures usually short, narrow, single, ragged. 



Position usually eccentric about 0.33 or 0.40 of 



longitudinal a.xis. 

 H. equestre: Form essentially the same as in H. vittatum. 



Position usually eccentric about 0.33 to 0.40 of 



longitudinal axis. 

 //. aulicum var. robustum: Form essentially the same as 



in H. vittatum. Position usually eccentric about 



0.33 to 0.40 of longitudinal axis. 



