GENUS IRIS. 



697 



I GV 



s 



Chart No. 262. 



S T CI CA PA FC P S CLPA CA 



Temperature Reaction. — The temperature of gelatinization is 66° to 67° C, mean 66.5°. 



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

 in 30 seconds. It is over in three-fourths of the grains in 10 minutes and in all in 15 minutes. It is 

 the same qualitatively as that of the grains of /. florentina. 



Reaction with chromic acid begins in a few grains at once and in all in 15 seconds. It is over in 

 70 seconds. It is the same qualitatively as that of the grains of /. florentina. 



The reaction with pyrogallic acid begins in all the grains in 15 seconds and is over in a minute. 

 It is qualitatively the same as that of the grains of /. florentina. 



Reaction with ferric chloride begins in a few grains in 45 seconds. It is over in nearly all in 8 

 minutes and in all in 12 minutes. It is the same qualitatively as that of the grains of /. florentina. 



The reaction with Purdy's solution begins in most grains in 45 seconds, some are partially 

 gelatinized in 5 minutes, and about half are nearly completely gelatinized in 30 minutes. It is the 

 same quahtatively as that of the grains of /. florentina. 



STARCH OF IRIS XIPHIUM VAR. LUSITANICA. (Plate 65, figs. 387 and 388. Chart 262.) 



Histological Characteristics. — In form the grains are generally simple. Compound grains, 

 aggregates, separated-grains with pressure facets, and a few clumps consisting of minute globular 

 grains are present as in 7. florentina; the surface is sometimes irregular. The irregularities are 

 generally due to a broadening of the proximal end; or to a curving of the distal end caused by the 

 addition of a secondary set of lamellae; or to rounded protuberances, which more often appear at 

 or near the proximal end. The conspicuous forms of the simple grains are cone-shaped with rounded 

 apex, ovoid, broadly triangular to clam-shell-shaped, and oval with squared end. In addition there 

 are large oval and curved club-shaped grains. The com- 

 pound grains are often irregular oval to broadly lenticular. 

 The aggregates consist either of equal-sized components, 

 or of one large grain with one very small, globular one. 

 The separated-grains are usually dome-shaped. The 

 grains are much broader in relation to length and more 

 regular in shape than those of I . florentina, and the cup- 

 shaped depression at the termination of the sets of lam- 

 ellae is not usually observed. The broadly triangular 

 to clam-shell-shaped forms are somewhat flattened. 



The hilum may appear as a clear, distinct, refrac- 

 tive spot which is centric in small, round forms, but in 

 the elongated grains is eccentric very slightly or from 

 two-fifths to one-third, usually two-fifths, of the longi- 

 tudinal axis. There is usually either a cavity or a cleft 

 at the hilum. There may be either one transverse or 

 diagonal cleft, or two or more clefts which generally 

 form a cross, or a figure like that of a flying bird, or of 

 a root-like form. They resemble those noted for I. 

 xiphium var. Grand Tresorier. 



The lamellce not distinct and the number can not be determined with certainty. When distinctly 

 visible they are rather coarse. One quite coarse, distinct lamella is frequently observed, either at 

 one-third or one-fourth of the distance from the hilum. 



The grains vary in size; the smaller are 3 by 3;u; the larger are 38 by 36/i and 32 by 20/x in length 

 and breadth. The common sizes are 24 by 18/x and 26 by 24/^ in length and breadth. 



Polariscopic Properties. — The figure is generally eccentric and quite distinct. The lines of the 

 figure are rather thick and generally are straight and broaden towards the margin. The figure is 

 fairly clear-cut and more distinct and regular than in /. florentina. 



The degree of polarization is rather high to quite high. There are variations in the different 

 grains as well as sometimes in the same aspect of a given grain. It is distinctly higher than in /. 

 florentina. 



With selenite the quadrants are fairly well defined, generally sHghtly irregular in shape, and 

 unequal in size. The colors are generally pure, but the yellow is sometimes not pure throughout 

 the entire quadrant. The colors are purer than in /. florentina. 



m 



Curve of Reaction- Intensities of Starch of Iris xiphium 

 var. Lusitanica. 



