GENUS TULIPA. 



637 



STARCH OF TULIPA AUSTRALIS. (Plate 34, figs. 203 and 204. Chart 140.) 



Histological Characteristics. — In form the grains are simple and isolated, with rare exceptions. 

 Small doublets are very rare, and there are no pressure facets. The surface of most grains is regular. 

 Irregularities may be caused by nipple-like processes either at one or both sides of the proximal 

 end, or rarely by the proximal end extending into a finger-like process, the axis of which may or may 

 not coincide with the longitudinal axis of the grain. The conspicuous forms among the larger grains 

 are triangular with curved base and rounded angles, somewhat clam-shell-shaped, and pyriform. 

 Among the smallest grains the chief forms are elliptical, ovoid, oval, flattened elliptical, and round. 

 The grains are flattened and when viewed on edge they frequently are seen to be narrower at the 

 distal end. The proportion of irregular grains is larger than in T. hageri. 



The hilum is a round fairly refractive spot with a range of eccentricity from one-fourth to 

 one-sixth, commonly not quite one-fifth, of the longitudinal axis of the grain. The hilum is some- 

 times marked by a short transverse fissure. 



The lamellce are fine and rather indistinct, with the exception of a few coarse lamellse which 

 form a band located at a distance ranging from about one-third to two-thirds between the hilum 

 and the distal end. There are sometimes on the large grains 3 disseminated, coarse, refractive lamellae 

 with groups of fine lamellse between them. The lamellae are not demonstrable throughout the grain, 

 but 24 to 28 lamellse can be made out on some grains. 



The size of the small grains is 6 by 6fi, of the larger 

 52 by 44ju, of the broader 30 by 32// in length and breadth. 

 The common size is 34 by 30/t in length and breadth. 



Polariscopic Properties. — The figure is usually eccen- 

 tric, distinct, and fairly clear-cut. Its lines are rather 

 thick and generally straight, and expanded at the margin 

 and distal end. In some grains the lines are either bent 

 or bisected. 



The degree of polarization is fairly high. There is 

 some variation in different grains, and even in the same 

 grain. It is rather higher than in T. hageri. 



With selenite the quadrants are fairly well defined, 

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

 quite pure, but the yellow is 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 not quite so deep as that of the grains of T. 

 hageri. After heating in water until all the grains are 



completely gelatinized, the solution colors fairly deeply and the swollen grains deeply on the addi- 

 tion of iodine. After boiUng for 2 minutes the solution colors very deeply and the grain-residues 

 lightly or not at all. The capsules 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 slightly more than others, and deeper than in T. hageri. 



With safranin the grains begin to stain at once and in 30 minutes are lightly colored. The stain 

 is deeper than that of the grains of T. hageri. 



Temperature Reaction. — The temperature of gelatinization is 52.7° to 54.8° C, mean 53.75°. 



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

 15 seconds. It is over in nearly all in 5 minutes and in all in 8 minutes. It is the same qualita- 

 tively as that of the grains of T. hageri. 



Reaction with chromic acid begins at once and is over in 40 seconds. It is the same qualita- 

 tively as that of the grains of T. hagen. 



Reaction with pyrogaUic add begins in a few seconds and is over in a minute. It is the 

 same qualitatively as that of the grains of T. hageri. 



Reaction with ferric chloride begins in a few grains in 15 seconds and is complete in all in 5 

 minutes. The reaction is the same qualitatively as that of the grains of T. hageri. 



With Purdy's solution the reaction begins in a few seconds and is over in 45 seconds. It is the 

 same qualitatively as that of the grains of T. hageri. 



Curve of Reaction-Intensities of Starch of 

 Tulipa australis. 



