GENUS IRIS. 



701 



to length and rather more regular in form than those; of /. florenlina. The aggregates and the fis- 

 sures at the hiluni bear a greater similarity to the grains of /. xiphlum var. Grand Tresorier than 

 to /. florenlina. 



The hilum may appear as a clear, distinct, refractive spot, centric in small, round forms, and 

 eccentric two-fifths to one-third, usually two-fifths, of the longitudinal axis in most of the grains. 

 There are sometimes two or more hila without a line of division in the siniijle grains. Either a cavity 

 or a cleft is usually found at the hilum. The clefts frequently are ragged and appear either in the 

 form of a cross, or of the flying-bird or dragon-fly type, or as a branched, root-like structure. 



The lamella are not very distinct, and the number can not be definitely decided; those visible 

 appear to be rather coarse. In some grains the lamellae were indistinct for one-third of the distance 

 from the hilum, and for the remainder of the grain 10 rather coarse and fairly distinct lamellae were 

 counted. In other grains 8 coarse lamellae were counted between the hilum and three-fourths of 

 the distance, and then a band located in the last one- 

 fourth consisting of 5 fine lamellae. 



The grains vary in size; the smaller are 3 by 3//; the 

 larger are 36 by 49/j and 36 by 28^ in length and breadth. 

 The common sizes are 24 by 30m and 28 by 22/; in length 

 and breadth. 



Polariscopic Properties. The figure is generally eccen- 

 tric and very distinct. Its lines are rather thick and may 

 be straight vnth broadening at the margin, but are either 

 bent or bisected in the greater number of grains. It is 

 fairly clear-cut, and more distinct than in 7. florenlina. 



The degree of polarization is high to very high, vnih 

 some variation in the same aspect of a given grain. 

 Polarization is markedly higher than in /. florenlina. 



With selenite the quadrants are well defined in some 

 grains and regular in shape and equal in size, while in many 

 grains they are not clearly defined, and are irregular in 

 shape and unequal in size. The colors are generally purer 

 than in I. florenlina. In several grains the yellow was not 

 quite pure and occasionally the same is noted for blue. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains all color a fairly deep violet- 

 blue; with 0.125 per cent solution they color lightly and the color does not deepen rapidly. After 

 heating in water until the grains are completely gelatinized, the solution colors fairly deeply and 

 the gelatinized grains very deeply on the addition of iodine. After boiling for 2 minutes the solu- 

 tion colors very deeply, but most of the grain-residues do not color at all. The capsules all color 

 a reddish-violet with an excess of iodine. 



Staining Reactions. With gentian violet and with safranin the grains all begin to stain at once 

 and in 30 minutes they are lightly stained, but slightly more than the grains of /. florenlina. 



Temperature Reaction. The temperature of gelatinization is 65 to 66 C, mean 65.5. 



Effects of Various Reagents. With chloral hydrate-iodine the reaction begins in 15 seconds. 

 It is over in one-third in 10 minutes, one-half in 17 minutes, in three-fourths in 40 minutes, and in 

 all in 60 minutes. There is a thin coating or outer layer of the grains which is affected first, other- 

 wise the reaction is qualitatively the same as that of the grains of I. florenlina. 



The reaction with chromic acid begins in some grains in 15 seconds, in all within 30 sec- 

 onds, and is over in 4 minutes. It is qualitatively the same as that of the grains of /. florenlina, 

 but the distal end does not appear to be much more sensitive to the reagent than the proximal 

 end or the sides. 



With pyrogaUic add some grains begin to react in 15 seconds and all in 30 seconds, and it is 

 over in 1% minutes. It is qualitatively the same as that of the grains of /. florenlina. 



The reaction with ferric chloride begins in many grains in a minute. Three-fourths of the grains 

 are completely gelatinized in 25 minutes and practically all in 50 minutes. It is qualitatively the 

 same as that of the grains of I. florenlina. 



Reaction with Purdy's solution begins in many grains in 45 seconds, and all are nearly completely 

 gelatinized in 5 minutes. It is the same qualitatively as that of the grains of 7. florenlina. 



Curve of Reaction-Intensities of Starch of Iris histrio. 



