704 



STARCHES OF IRIDACEiE. 



that of the grains of 7. florentina. After heating in water until the grains are completely gelatinized, 

 the solution and the gelatinized grains color deeply on the addition of iodine. After boiling for 2 

 minutes the solution colors very deeply, but most of the grain-residues not 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 fairly stained, and more than the grains of I. florentina. 



Temperature Reaction. The temperature of gelatinization is 64 to 65 C, mean 64.5. 



Effects of Various Reagents.- With chloral hydrate-iodine reaction begins in most grains in 30 

 seconds. It is over in one-half in 10 minutes and in nearly all in 15 minutes. It is the same quali- 

 tatively as that of the grains of /. florentina. 



The reaction with chromic acid begins in some grains in 15 seconds, in all in 45 seconds, and 

 is over in 2 minutes. It is the same qualitatively as that of the grains of /. florentina. 



The reaction with pyrogallic acid begins in 10 to 15 seconds and is over in IJ^ minutes. It is 

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



With ferric chloride the grains begin to react in many grains in 30 to 45 seconds. The reaction 

 is over in half of the grains in 15 minutes, in nearly all in 30 minutes, and in all in 40 minutes. It is 

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



With Purdy's solution the reaction begins in many grains in 20 seconds. Most of the grains 

 are nearly completely gelatinized in 5 minutes and all are completely gelatinized in 8 minutes. It 

 is the same qualitatively as that of the grains of I. florentina. 



Differentiation of the Starches of the Genus Iris. 



Histological Characteristics. 

 Conspicuous Forms. 



I. florentina: Usually simple. Some compound, small ag- 

 gregates, grains with few pressure facets. Often 

 irregular with rounded protuberances and second- 

 ary deposits of starch. Cup-shaped depressions at 

 the distal end of primary sets of lamellae, and 

 frequently of secondary sets. Elongated ovoid with 

 squared, hollowed, distal end; oval, finger-shaped, 

 and conical with rounded apex. Both compound 

 and aggregate grains consisting of a large grain 

 with a small grain fitting into its distal end. 



/. pallida var. speciosa: Essentially the same as in /. 

 florentina, but not so irregular in outline, and 

 shortened and broader forms are proportionately 

 more numerous. 



/. pumila var. cyanea: Essentially the same as in /. 

 florentina, but more irregular, and the grains are 

 mostly elongated. 



I. bismarckiana: The same as in /. florentina, but the 

 grains tend to be broader in proportion to length; 

 conical grains with rounded apex are more numer- 

 ous; small grains attached to large grains often 

 at the side instead of at distal end; depression at 

 end not so deep; compound, broadly lenticular 

 frequently found. 



I. iberica: The same as in /. bismarckiana. 



I. xiphium var. Grand Tresorier: Cone-shaped with rounded 

 apex, ovoid with squared distal end, and clam-shell- 

 shaped. Compound grains similar to /. florentina, 

 except minute globular grains more frequently 

 found at lines of union of components, more regular 

 in outline, and broader in proportion to length. 

 Otherwise same as in /. florentina. 



I. xiphium var. Wilhebnine: Ovoid with squared distal 

 end, oval, broadly triangular with curved base 

 and rounded angles, pyriform, and small globular. 

 Grains broader in proportion to length than in 

 I. florentina. Otherwise the same as in I. floren- 

 tina. 



I. xiphium var. lusitanica: Cone-shaped with rounded 

 apex, ovoid, broadly triangular to clam-shell- 

 shaped, oval with squared end, broader in relation 

 to length. Otherwise essentially the same as in 

 /. florentina. 



Histological Characteristics. Continued. 



Conspicuous Forms. Continued. 



/. tingitana: Broadly triangular with rounded angles to 

 clam-shell-shaped, cone-shaped with rounded apex. 

 More uniform in shape and much broader in rela- 

 tion to length than in /. florentina. They bear 

 closer resemblance to /. xiphium var. Ixisitanica 

 than to /. florentina. 



I. reticulata: Cone-shaped with rounded apex, pyriform 

 with squared ends, globular, good-sized, and minute, 

 oval with or without squared end; irregular oval. 

 Less irregular and broader in proportion to length 

 than in /. florentina. Otherwise essentially the 

 same as in /. florentina. 



I. histrio: Cone-shaped with rounded apex, broadly trian- 

 gular with rounded angles to clam-shell and oyster- 

 shell shapes, ovoid with squared end. Less irreg- 

 ular, and broader in proportion to length than in 

 /. florentina. Otherwise essentially the same as 

 in /. florentina. 



I. alata: Elongated ovoid with squared distal end; 

 pyriform with squared distal end, oval with broad- 

 ened distal end, and numerous small globular 

 grains. Compound grains and aggregates more 

 numerous, and grains are broader in relation to 

 length than in /. florentina, but otherwise essen- 

 tially the same. 



I. caucasica: Irregular ovoid, elongated oval with squared 

 distal end, and round with squared distal end. Cup- 

 shaped depressions at distal end not so marked as 

 in /. florentina. Otherwise about the same as in 

 /. florentina. 



Hilum Form, Number, and Position. 



I. florentina: Form distinct round spot or cavity; may 

 be fissured; single short, straight transverse cleft, 

 or cross or stellate fissures. Position usually 

 eccentric 0.33 to 0.16, commonly 0.25, of longitud- 

 inal axis. 



I. pallida var. speciosa: Form distinct round or elliptical 

 spot; occasionally fissured diagonally or trans- 

 versely; less often fissured than in /. florentina, 

 and unfissui'ed hilum less refractive. Position 

 usually eccentric about 0.25 to 0.12 of longitudinal 

 axis. 



