GENUS DIEFFENBACHIA. 



469 



Differentiation of Certain Starches of the Pith of the Genus Dieffenhachia. 



Histological Characteristics. 

 Consyicuous Forms. 



D. seguine var. nobilis: Simple and compound. Elon- 

 gated ellipses with tendency to one broadly 

 lanceolate end and one flattened end; boot-shaped, 

 T-shaped, boomerang-shaped, and related forms 

 due to secondary deposists of lamella; also round, 

 ovoid, and oval forms, etc. 



D. seguine var. maculala: Grains show great tendency 

 to broadness and roundness, and to a far greater 

 variety of forms that are due to the deposition of 

 secondary deposits than in the case of the pre- 

 ceding starch. The T and boot shapes and 

 related forms are relatively very numerous. 



D. seguine var. irrorala: Same as D. seguine var. nobilis, 

 except that there is less tendency to a pointing 

 of the broadly lanceolate end and even a lower 

 proportion of grains having secondary deposits of 

 lamella;, and hence of freakish forms. 



D. illuslris: Grains more like those of D. seguine var. 

 nobilis and D. seguine var. irrorala than D. seguine 

 var. maculala. Tendency to hooked forms very 

 marked. 



Hilum — Form, Number, and Posilion. 



D. seguine var. nobilis: Form small, round, single, fissura- 

 tion common and usually ragged, fairly distinct. 

 Position eccentric in elongated grains about 0.3 to 

 0.4 of longitudinal axis of grain. 



D. seguine var. maculala: Form comparatively large, 

 round, single, sometimes fissured, distinct. Posi- 

 tion eccentric 0.4 to 0.2 of longitudinal axis. 



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

 var. nobilis, but not fissured. Position eccentric 

 about 0.4 of longitudinal axis. 



D. illv^tris: Form small, round, single, rarely fissured, 

 fairly distinct. Position eccentric about 0.3 to 0.4 

 of longitudinal axis. 



Lamella — General Characteristics and Number. 



D. seguine var. nobilis: Distinct, continuous, fine, regular 

 or irregular circles, ellipses, or segments of circles 

 or ellipses; two sets in many grains, the secondary 

 being coarser than the primary. About 35 on an 

 average or medium-sized grain. 



D. seguine var. maculala: Same as in i). seguine var. rwbUis, 

 except that both primary and secondary lamellae are 

 not so fine. About 40 on an average grain. 



D. seguine var. irrorala: Same as in D. seguine var. nobilis. 

 About 30 on an average grain. 



D. illuslris: Same as in D. seguine var. nobilis. About 

 30 on an average grain. 



Size. 

 D. seguine var. nobilis: From 5 to 60ju, commonly 35^. 

 D. seguine var. mactdata: From 10 to 70^, commonly 40;u. 

 D. seguine var. irrorala: From 5 to 40m, commonly 27^. 

 D. illuslris: From 7 to 60^, commonly 35/x. 



PoLARiscopic Properties. 

 Figure. 



D. seguine var. nobilis: Usually very eccentric, distinct, 

 distorted; modified according to shape and struc- 

 ture of grain. 



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

 seguine var. nobilis. 



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

 seguine var. nobilis. 



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

 nobilis. 



Degree of Polarization. 



D. seguine var. nobilis: F'airly high. 



D. seguine var. maculala: Very high, much higher than 

 in D. seguine var. nobilis. 



PoLARiscopic Properties. — C!ontinued. 

 Degree of Polarization. — Continued. 



D. seguine var. irrorala: Fairly high, but distinctly lower 



than in D. seguine var. nobilis. 

 D. illuslris: High, higher than in D. seguine var. nobilis. 



Polarization with Selenile — Qttadranls and Colors. 



D. seguine var. nobilis: Quadrants well-defined, irregular 



in shape and size. Colors fairly pure. 

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



var. nobilis. Colors pure, purer than in D. seguine 



var. nohilis. 

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



var. nobilis. Colors fairly pure, but less pure than 



in D. seguine var. nobilis. 

 D. illuslris: Quadrants same as in D. seguine var. nobilis. 



Fairly pure, better than in D. seguine var. nobilis. 



Iodine Reactions. 



Intensity and Color. 



D. seguine var. nobilis: Deep; blue-violet. 



D. seguine var. maculala: Deep, deeper than in D. seguine 



var. nobilis; blue-violet. 

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



var. nobilis; blue-violet. 

 D. illuslris: Deep, deeper than in D. seguine var. nobilis; 



blue- violet. 



Staining Reactions. 



With Gentian Violet. 



D. seguine var. nobilis: Deep. 



D. seguine var. maculata: Deep, deeper than in D. seguine 



var. nobilis. 

 D. seguine var. irrorala: Deep, deeper than in D. seguine 



var. nobilis. 

 D. illuslris: Deep, same as in D. seguine var. nobilis. 



With Safranin. 



D. seguine var. nobilis: Deep. 



D. seguine var. maculala: Deep, deeper than in D. seguine 



var. nobilis. 

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



nobilis. 

 .D. illuslris: Deep, less than in D. seguine var. nobilis. 



Temperature op Gelatinization. 



D. seguine var. nobilis: 68 to 70° C, mean 60°. 

 D. seguine var. maculata: 70 to 71° C, mean 70.5°. 

 D. seguine var. irrorala: 68.5 to 69.5° C, mean 69°. 

 D. illuslris: 69 to 70° C, mean 69.5°. 



Effects of Various Reagents. 

 Reaction with Chloral Hydrate-Iodine. 



D. seguine var. nobilis: Begins in most of the grains in 



a minute; complete in half in 10 minutes, and in 



all in 30 minutes. 

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



in five-sixths in an hour. 

 D. seguine var. irrorala: Begins in a minute; complete 



in 40 minutes. 

 D. illuslris: Begins in 2 minutes; complete in three-fourths 



in 30 minutes. 



Reaction with Chromic Acid. 



D. seguine var. nobilis: Begins in 15 seconds; complete 

 in 3J^ minutes. 



D. seguine var. maculata: Begins in IJ^ minutes; com- 

 plete in 5J^ minutes. 



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

 in 4 minutes. 



D. illuslris: Begins in a minute; complete in 4 minutes. 



