470 



STARCHES OF AROIDE^. 



Differentialion of Certain Starches of the Pith of the Genus Dieffenbachia. — Continued. 



Effects of Various Reagents. — Continued. 

 Reaction with Pyrogallic Acid. 



D. seguine var. nobilis: Begins in 30 seconds; complete 

 in 5 minutes. 



D. seguine var. maculala: Begins in 11^ minutes; com- 

 plete in 7 minutes. 



D. seffuine var. irrorala: Begins in 1 minute; complete 

 in 8 minutes. 



D. iUuslris: Begins in IJ^ minutes; complete in 10 min- 

 utes. 



Reaction loith Ferric Chloride. 



D. seguine var. nobilis: Begins in 2 minutes; complete in 

 all in 20 minutes. 



D. seguine var. maculala: Begins in 2 to 5 minutes; com- 

 plete in 25 minutes. 



D. seguine var. irrorala: Begins in 2 minutes; complete 

 in 15 minutes. 



Effects of Various Reagents. — Ck)n tinned. 



Reaction ivilh Ferric Chloride. — Continued. 



D. iUustris: Begins in 2 minutes; complete in 30 minutes. 



Reaction with Purdy's Solution. 



D. licguine var. nobilis: Begins in a minute; in 45 minutes 



all the grains are partially but none completely 



gelatinized; practically no furtiier reaction in an 



hour. 

 D. seguine var. maculala: Begins in some in 2 minutes. 



In 1 }^ hours about half of the grains are partially 



gelatinized. 

 D. seffuine var. irrorala: Begins in one-third in 2)4 



minutes. In IJ^ hours all are partially gelatinous. 

 D. iUustris: Begins in 2 minutes. In 1 1^ hours not more 



than about one-fourth of the grains show any 



signs of gelatinization. 



Differentialion of Certain Starches of the Cortex of the Genus Dieffenbachia. 



D 



Histological Characteristics. 

 Conspicuous Forms. 

 seguine var. nobilis: Essentially the same as in pith 

 starch, excepting that the grains are almost 

 wholly of the cylindrical and elliptical types. 

 Secondary lamellae rare. 



D. seguine var. maculala: Essentially the same as in 

 pith starch, except a marked tendency to the 

 elliptical form, and to less of the peculiar odd 

 shapes due to secondary lamellse. 



D. seguine var. irrorala: Essentially the same as in pith 

 starch, but with marked tendency to the elliptical 

 form and to a lessening in the number of freakish 

 forms due to secondary lamellse. 



D. iUuslris: Essentially the same as pith starch, but 

 the grains are narrower, with much greater tend- 

 ency to hook forms. 



Hilum — Form, Number, and Position. 

 D. seguine var. nnbUis: Form the same as in the pith, 



but not fissured. Position more eccentric than 



in pith starch. 

 D. seguine var. maculala: Form same as in the pith. 



Position eccentric, about the same as in pith starch. 

 D. seguine var. irrorala: Form same as in the pith. 



Position eccentric, about the same as in pith starch. 

 D. iUustris: Form fairly distinct, small, round, not fissured. 



Position eccentric, about the same as in pith starch. 



LameUce — General Characteristics and Number. 



D. seguine var. nobilis: Same aa in the pith, but finer. 

 Number about the same as in pith starch. 



D. seguine var. m,acuUUa: The same as in the pith. Num- 

 ber not so many, as a rule, as in pith starch. 



D. seguine var. irrorala: Form same as in the pith. Num- 

 ber about the same as in pith starch. 



D. iUuslris: Form about the same as in pith starch, but 

 somewhat less distinct. Number about the same 

 as in pith starch. 



Size. 



D. seguine var. nobilis: From 4 to 49m, commonly 24^. 



D. seguine var. maculala: From 7 to 52/^, commonly 27m. 



D. seguine var. irrorala: From 4 to 47m, commonly 27m. 



D. iUustris: From 5 to 50m, commonly 25m. 



PoLARiBcopic Properties. 

 Figure. 

 D. seguine var. nobUis: The same as in pith starch, but 



more eccentric. 

 D. seguine var. maculala: The same as in pith starch. 

 D. seguine var. irrorala: The same as in pith starch. 

 D. iUuslris: The same as in pith starch. 



PoLABiecopic Properties. — Continued. 



Degree of Polarization. 



D. seguine var. nobilis: Fair, lower than in pith starch. 

 D. seguine var. maculala: High, lower than in pith starch. 

 D. seguine var. irrorala: Fair, distinctly lower than in 



pith starch. 

 D. iUustris: Fairly high, not so high as in pith starch. 



Polarization wUh Selenite — Quadrants and Colors. 



D. seguine var. nobilis: Quadrants same as in pith starch. 



Colors with lower purity than in pith starch. 

 D. seguine var. maculala: Quadrants same as in pith 



starch. Colors same as in pith starch. 

 D. seguine var. irrorala: Quadrants same as in pith starch. 



Colors same as in pith starch. 

 D. iUuslris: Quadrants same as in pith starch. Colors 



with lower purity than in pith starch. 



Iodine Reactions. 

 Intensity and Color. 



D. seguine var. nobUis: Deep, the same as in pith starch; 

 blue- violet. 



D. seguine var. macidata: Deep, the same as in pith starch ; 

 blue-violet. 



D. seguine var. irrorala: Deep, deeper than in pith starch; 

 blue-violet. 



D. iUustris: Deep, not so deep as in pith starch; blue- 

 violet. 



Staining Reactions. 



WUh Gentian Violet. 



D. seguine var. nobUis: Deep, lighter than in pith starch. 

 D. seguine var. maculala: Deep, same as in pith starch. 

 D. seguine var. irrorala: Deep, same as in pith starch. 

 D. iUustris: Deep, lighter than in pith starch. 



With Safranin. 



D. seguine var. nobilis: Fairly deep, not so deep as in 



pith starch. 

 D. seguine var. maculala: Fairly deep, not so deep as in 



pith starch. 

 D. seguine var. irrorala: Fairly deep, not so deep as in 



pith starch. 

 D. iUustris: Fairly deep, not so deep as in pith starch. 



Temperature of Gelatinization. 



D. seguine var. nobUis: 68.5 to 70.5° C, mean 69°. 

 D. seguine var. maculala: 70 to 71.2° C, mean 70.6°. 

 D. seguine var. irrorala: 68 to 69.5° C, mean 68.75°. 

 D. iUuslris: 69 to 71° C, mean 70°. 



