GENUS TULIPA. 



535 



PS CI PA I 

 " PC PS 



Curve of Reaction-Intensities of Starch of Tulipa 

 oculus-solis. 



The hilum is an indistinct, romul spot, generally with a range of eccentricity from one-fourth 

 to one-sixth, usually one-fifth, of the longitudinal diameter. It is ordinarily not fissured, and occa- 

 sionally a small cavity may appear in it. 



The lamella near the hilum are not usually demonstrable, but when observed they form com- 

 plete rings, but near the margin and distal end they assume the shape of the outline of the grains, 

 and arc generally coarser and more distinct. Manj^ grains have two or three more refractive, coarser 

 lamellse at varying points on the grain. On account of the indistinctness of the lamellae their num- 

 ber can not be accurately determined throughout the grain, but rarely 30 to 32 arc demonstrable. 



The size of the small grains is 6 by G;u, of the larger, broailened grains is 52 by -19;u, and of the 

 elongated grains 60 by 42yu in length and breadth. The 

 common size of the broadened grains is 34 by 36yu and of 

 the elongated grains is 38 bj- 22^ in length and breadth. 



Polariscopic Properties.- The figure is usually eccen- 

 tric, distinct, and fairly clear-cut. Its hues are thick and 

 usually straight, and expanded at the proximal and distal 

 margins, rarely either bent or bisected. The figure is the 

 same as in T. hageri. 



The degree of polarization is fairly high, but varies 

 in different grains and in the same aspect of a given grain. 

 It is higher than in T. hageri. 



With selenite the quadrants are fairly well defined 

 and regular in shape, unequal in size. The blue is quite 

 pure, the yellow not pure, as in T. hageri. 



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

 tion the grains color a deep blue-violet; with 0.125 per 

 cent solution they color fairly and the color deepens rap- 

 idly. It is the same as that of the grains of T. hageri. 

 After heating in water until all the grains are com- 

 pletely gelatinized, the solution colors fairly deeply and 



the swollen grains deeply on the addition of iodine. After boiling for 2 minutes the solution colors 

 very deeply and the grain-residues lightly or not at all. The capsules all color a red-violet with 

 a slight excess of iodine. 



Staining Reactions. With gentian violet the grains begin to stain at once and in 30 minutes 

 are fairly deeply stained, some more than others. The color is deeper than that of the grains of 

 T. hageri. 



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

 some more than others. The color is deeper than that of the grains of T. hageri. 



Temperature Reaction.- ^The temperature of gelatinization is 56.2 to 58 C, mean 57.1. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins in all in 30 seconds. 

 It is over in nearly all the grains in 5 minutes and in all in 10 minutes. It is the same qualitatively 

 as that of the grains of T. hageri, except that there is no bubble formation at the hilum. 



With chromic add reaction begins in a few seconds and is over in a minute. It is the same 

 qualitatively as that of the grains of T. hageri, except that there is no bubble formation at the 

 hilum. 



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

 same qualitatively as that of the grains of T. hageri, except that there is no bubble formation at 

 the hilum. 



The reaction with ferric chloride begins in a few grains in 20 seconds. It is over in nearly all 

 in 4 minutes and in all in 8 minutes. It is the same qualitatively as that of the grains of T. hageri. 



With Purdy's solution reaction begins in 20 seconds and is over in 1^ minutes. It is the same 

 qualitatively as that of the grains of T. hageri, except that there is no bubble formation at the hilum. 



STARCH OF TULIPA PRECOX. (Plate 34, figs. 201 and 202. Chart 139.) 

 Histological Characteristics. In form the grains are simple and with the exception of very few 

 doublets are isolated. There are no pressure facets on the isolated grains. The surface of most 

 grains is regular. Some grains have lateral or proximal nipple-like protuberances, and rarely the 

 36 



