764 



STARCHES OP IRIDACE^. 



Differentiation of Certain Starches of the Genus Ixia. 



BbsTOLOGiCAii Characteristics. 

 Conspicuous Forms. 



I. speciosa: Simple, many aggregates, usually in the 

 form of doublets and triplets, 1 to 3 or more 

 pressure facets on isolated grains. Hemispherical 

 with 1 to 3 pressure facets at base, spherical, 

 spherical to oval and elliptical. 



/. viridiflora: Essentially the same as in /. speciosa. 



I. var. (Emma): Essentially the same as in /. speciosa. 



Hilum Form, Number, and Position. 



I. speciosa: Form comparatively large, round, distinct, 



rarely fissured, fissures single, short, transverse. 



Position usually shghtly eccentric. 

 /. viridiflora: Form essentially the same as in I . speciosa. 



Position usually slightly eccentric. 

 /. var. (Emma): Form essentially the same as in /. 



speciosa. Position usually slightly eccentric. 



Lamellae General Characlerislics and Number. 



I. speciosa: Fairly distinct, rather coarse, regular con- 

 tinuous rings of same shape as the grain when 

 distal to the hilum. About 4 to 6 on larger grains. 



/. viridiflora: Essentially the same as in /. speciosa. 

 About 5 to 6 on the larger grains. 



/. var. (Emma): Essentially the same as in /. speciosa. 

 About 5 to 6 on the larger grains. 



Size. 



I. speciosa: From 2 to 18m, commonly 12m. 

 /. viridiflora: From 2 to 17m, commonly 12m. 

 /. var. {Emma): From 2 to 20m, commonly 14m. 



PoLABiscopic Properties. 



Figure. 



I. speciosa: Usually eccentric, fairly distinct, usually 



clear-cut. 

 /. viridiflora: The same as in /. speciosa. 

 I. var. {Emma): The same as in /. speciosa. 



Degree of Polarization. 



I. speciosa: Fair, somewhat variable. 



/. tnridiflora: Fair, somewhat variable, lower than in /. 



speciosa. 

 I. var. {Emma): Fair, somewhat variable, shghtly 



higher than in /. speciosa. 



Polarization with Selenite Quadrants and Colors. 



I. speciosa: Quadrants fairly well defined, generally 

 regular, unequal in size. Colors pure. 



/. viridiflora: Quadrants the same as in /. speciosa. 

 Colors pure. 



/. var. {Emma): Quadrants the same as in /. speciosa. 

 Colors pure. 



Iodine Reactions. 



Intensity and Color. 



I. speciosa: Fairly deep; blue- violet. 

 /. viridiflora: Fairly deep, less than in /. speciosa; blue- 

 violet. 



Iodine Reactions. Continued. 



Intensity and Color. Continued. 



/. var. {Emma): Fairly deep, less than in /. speciosa; 

 blue-violet. 



Staining Reactions. 

 With Gentian Violet. 

 I. speciosa: Light. 



/. viridiflora: Light, more than in /. speciosa. 

 I. var. {Emma): Light, shghtly less than in /. speciosa. 



With Safranin. 

 I. speciosa: Fair. 



/. viridiflora: Fair, more than in /. speciosa. 

 I. var. {Emma): Fair, less than in I. speciosa. 



Tempehature op Gelatinization. 



/. speciosa: 83 to 85 C, mean 84. 



I. viridiflora: 82 to 84 C, mean 83. 



/. var. {Emma): 84 to 85 C, mean 84.5. 



Effects of Various Reagents. 

 Reaction with Chloral Hydrate-Iodine. 



I. speciosa: Begins in all in 20 seconds; complete in all 



in 8 minutes. 

 /. viridiflora: Begins in some in 30 seconds; complete in 



12 minutes. 

 /. var. (Emma): Begins in most in 45 seconds; complete 



in nearly all in 20 minutes. 



Reaction with Chromic Acid. 



I. speciosa: Begins in all in 5 seconds; complete in all 



in IH minutes. 

 /. viridiflora: Begins in all in 15 seconds; complete in 



all in \% minutes. 

 /. var. {Emma:) Begins in all the grains in 15 seconds; 



complete in all in 2 minutes. 



Reaction ivith Pyrogallic Acid. 



I. speciosa: Begins in all in 30 seconds; complete in all 



in 10 minutes. 

 /. viridiflora: Begins in all in 45 seconds; complete in 



all in 18 minutes. 

 7. var. {Emma): Begins in all in 60 seconds; complete 



in all in 17 minutes. 



Reaction with Ferric Chloride. 



I. speciosa: Begins in many in 30 seconds; complete in 



all in 8 minutes. 

 /. viridiflora: Begins in many in 45 seconds; complete 



in all in 15 minutes. 

 I. var. (Emma): Begins in most in 45 seconds; complete 



in all in 20 minutes. 



Reaction with Purdy's Solution. 



I. speciosa: Begins in most in 13^^ minutes; nearly com- 

 plete in all in 30 minutes. 



I. viridiflora: Begins in some in 3 minutes; nearly com- 

 plete in aU in 30 minutes. 



I. var. {Emma): Begins in a few grains in 2 minutes; 

 nearly complete in all in 30 minutes. 



NOTES ON THE STARCHES OF LXIA. 



The three Ixia starches show no essential histological differences, and the correspondence be- 

 tween their reactions is close. However, I. speciosa could with readiness be distinguished from the 

 other two, which latter could also be diagnosed, one from the other. 



