GENUS ALSTRCEMERIA. 



663 



Differentiation of Certain Starches of the Genus Alstrmmeria. Continued. 



Histological Characteristics. Continued. 

 Hilum Form, A'umber, and Position. Continued. 

 A. auranliaca {aurea): Form rather distinct, rather large 

 round spot ; may be multiple; nearly always fissured, 

 fissure or fissures large, deep, irregular and ragged, 

 or a great number of fine radiating fissures. Posi- 

 tion centric to eccentric about 0.40 to 0.33 of the 

 longitudinal axis. 



Lamellce General Characterisiics and Number. 



A. ligtu: Not very distinct, rather coarse, regular, concen- 

 tric rings. 4 to 9 on larger grains, probably more. 



A. hrasiliensis: Not very distinct, rather fine, regular 

 circles or segments of circles. 18 to 24 on larger 

 grains. 



A. auranliaca {aurea): Fairly distinct, rather coarse, regu- 

 lar rings or ellipses or segments of elUpses. 18 to 24 

 on larger grains. 



Size. 



A. ligtu: From 8 to IQy., commonly SO/i (simple). 



A. brasUiensis: From 10 to 48m, commonly 30m (simple). 



A. auranliaca {aurea): From 18 to 69m, commonly 40m 

 (simple) . 



PoLARiscopic Properties. 



Figure. 



A. ligtu: Eccentric, distinct, not always clear-cut, often 



distorted and double multiple. 

 .4. brasUiensis: Usually very eccentric, distinct, usually 

 clear-cut, at times somewhat distorted, rarely 

 double or multiple figures. 

 A. auranliaca (aurea): Somewhat eccentric, fairly clear- 

 cut, fairly regular, occasionally double or multiple 

 figures. 



Degree of Polarization. 



A. ligtu: Veiy high. 



A. brasUiensis: High, not so high as in yl. ligtu. 

 A. auranliaca {aurea): Very high, shghtly higher than in 

 A. ligtu. 



Polarization with Selenite Quadrants and Colors. 

 A. ligtu: Quadrants usually fairly well defined, usually 

 very irregular in shape, and unequal in size. Colors 

 fairly pure. 

 A. brasUiensis: Quadrants usually well defined, irregular 



in shape, and unequal in size. Colors fairly pure. 

 A. auranliaca {aurea): Quadrants not well defined, fairly 

 regular in shape, but unequal in size. Colors fairly 

 pure. 



Iodine Reactions. 

 Intensity and Color. 



A. ligtu: Very deep; blue- violet. 



A. brasUiensis: Very deep, deeper than in .4. ligtu; blue- 

 violet. 



A. auranliaca (aurea): Very deep, less deep than in A. 

 ligtu; blue-violet. 



Staining Reactions. 

 With Gentian Violet. 

 A. liglu: Deep. 

 .4. brasUiensis: Very deep, much deeper than in A. 



ligtu. 

 A. auranliaca (aurea): Deep, slightly deeper than in A. 

 liglu. 



With Safranin. 

 A liglu: Deep. 

 A. brasUiensis: Very deep, much deeper than in A. 



ligtu. 

 A. auranliaca (aurea): Deep, slightly deeper than in A. 



ligtu. 



Temperature of Gelatinization. 

 A. liglu: 58 to 59 C, mean 58.5. 

 A. brasUiensis: 57 to 58.5 C, mean 57.75. 

 A. auranliaca (aurea): 53.5 to 56 C, mean 54.75. 



Effects of Various Reagents. 

 Reaction with Chloral Hydrate-Iodine. 

 A. ligtu: Begins in 45 seconds; complete in 7 minutes. 

 A. brasUiensis: Begins in 30 seconds; complete in 6 min- 

 utes. 

 A. auranliaca (aurea): Begins in 30 seconds; complete in 

 four-fifths in 9 minutes, and in all in 17 minutes. 



Reaction with Chromic Acid. 



A. liglu: Begins in a few seconds; complete in 30 sec- 

 onds. 



A. brasUiensis: Begins in a few seconds; complete in 30 

 seconds. 



A. auranliaca (aurea): Begins in 15 seconds; complete in 

 IM minutes. 



Reaction with Pyrogallic Add. 



A. ligtu: Begins in 20 seconds; complete in 2J^ min- 

 utes. 



A. brasUiensis: Begins in 15 seconds; complete in 2 min- 

 utes. 



.4. auranliaca (aurea): Begins in 30 seconds; complete in 

 4 minutes. 



Reaction with Ferric Chloride. 



A. liglu: Begins in a few in 30 seconds; complete in 15 

 minutes. 



A. brasUiensis: Begins in a few in 60 seconds; complete 

 in 14 minutes. 



A. auranliaca (aurea): Begins in a few in 30 seconds; com- 

 plete in 20 minutes. 



Reaction with Purdy's Solulion. 



A. liglu: Begins at once; complete in 30 seconds. 

 A. brasUiensis: Begins at once; complete in 30 seconds. 

 A. auranliaca (aurea): Begins in a very few seconds; com- 

 plete in 30 seconds. 



NOTES ON THE STARCHES OF ALSTRCEMERIA. 



The most noticeable differences in the appearances of the Alslrcemeria starches are in relation 

 to the abundance of compound grains in A. ligtu; the very conspicuous fissuration of A. auranliaca 

 {aurea) ; the differences in the distinctness, coarseness, and fineness of the lamellae, and in the sizes 

 of the grains. The differences in the interference figures are verj^ conspicuous, owing to relative 

 numbers of compound and single grains in the two starches. In the reactions, differences of impor- 

 tance are noted in almost every record, and the sensitivity of the starches to the various reagents is 

 very marked. On the whole, the starch of A. brasUiensis is the most sensitive. A. liglu in compari- 

 son with A. auranliaca (aurea) is less responsive in the color and heat reactions, but more respon- 

 sive, on the whole, with the chemical reagents. 

 44 



