GENUS TULIPA. 531 



The size of the smallest grains is 6 by Qn and of the largest 58 by 34/u. The common size is 

 36 by 2ifi. 



Polnriscnpic Propel lies. The figure is usually eccentric. Its lines are thick and usually straight 

 and somewhat expanded at the proximal and distal margins. Occasionally its lines are either bent 

 or bisected, and have a greater tendency to distortion than in other Tulipa. The figure is the same 

 as that of T. hageri. 



The degree of polarization is fairly high. It varies somewhat in different grains and also in 

 the same aspect of a given grain. It is not quite so high as in T. hageri. 



With selenile the quadrants are fairly well defined, frequently irregular 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 solution the grains color a deep blue-violet; 

 with 0.125 per cent solution they color fairly and the color deepens rapidly. The color is not 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 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 

 they are fairly stained. They stain more than the grains of T. hageri. 



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

 The stain is deeper than in the grains of T. hageri. 



Temperature Reaction. The temperature of gelatinization is 50.2 to 51.7 C, mean 50.95. 



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

 30 seconds. It is over in nearly all in 5 minutes and in all in 17 minutes. It is the same quali- 

 tatively as that of the grains of T. hageri. 



With chromic acid reaction begins at once and is over in 50 seconds. It is the same qualitatively 

 as that of the grains of T. hageri. 



Reaction with pyrogallic acid begins in a few seconds and is over in 40 seconds. It is the same 

 qualitatively as that of the grains of T. hageri. 



The reaction \vith ferric chloride begins in a few grains in 15 seconds. It is over in nearly all 

 in 4 minutes and in all in 6 minutes. 



Reaction with Purdy's solution begins in a verj' few seconds and is over in a minute. It is 

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



STARCH OF TULIPA DIDIERI VAR. FRANSONIANA. (Plate 33, figs. 193 and 194. Chart 135.) 



Histological Characteristics. ^In form the grains are simple, and, with the exception of some 

 small aggregates, mostly in the form of triplets, they arc isolated. Few pressure facets were noted 

 on the isolated grains. The surface of most of the grains is regular. Irregularities are rare, and 

 when found are usually caused by small protuberances at or near the proximal end, such as hereto- 

 fore noted under other Tulipa. The conspicuous forms among the large grains are the broadly 

 triangular with curved base and rounded angles to clam-shell shape, the narrow triangular to 

 somewhat pyriform and rare flattened pyriform and Indian flint arrow-head shape. The smallest 

 forms are slightly flattened oval, ovoid, pyriform and round. The grains are flattened and when 

 viewed on edge they are frequently narrower at the distal end. 



The hilurn is a round, refractive spot, with a range of eccentricity from one-fourth to one-flfth, 

 commonly one-fourth, of the longitudinal axis. A transverse cleft is frequently foimd at the hilum. 



The lamellce are usually fine and indistinct in the larger part of the grain. When distinct, those 

 near the hilum form complete rings, but those nearer the margin assume the shape of the grain and 

 appear to be incomplete. One quite coarse and refractive lamella is frequently found near the distal 

 margin, between which point and the margin there is usually a band of quite fine lamellae. Rarely 

 the lamellae may be observed throughout most of the grain, and about 30 have been recorded. 



The size of the smaller grains is 6 by 6m, of the larger grains 50 by 44/i, of the broadened grains 

 44 by 46/i, in length and breadth. The common size of the narrower grains is 36 b}^ 30|Lt, of the 

 broader grains 34 by 36^ in length and breadth. 



Polariscopic Properties. The figure is usually eccentric. It is distinct and fairly clear-cut. 

 Its lines are thick and straight and are expanded near the distal and proximal margins. In rare 

 cases the lines are either bent or bisected. 



