386 



STARCHES OF LEGUMINOSiE. 



Differentiation of Certain Starches 



Effects of Various Reagents. 

 Reaction with Chloral Hydrate-Iodine. 



V. saliva: Begins in some in 30 seconds; complete in three- 

 fourths in 30 minutes, and in nine-tenths in an 

 hour. 



V. villosa: Begins in some in 20 seconds; complete in 

 four-fifths in 30 minutes, and in nine-tenths in an 

 hour. 



V. faba: Begins in some in 20 seconds; complete in three- 

 fourth in 30 minutes, and in seven-eighths in an 

 hour. 



V.fulgens: Begins in some in 20 seconds; complete in 

 two-thii3s in 30 minutes, and in five-sixths in an 

 hovar. 



V. gerardi: Begins in some in 20 seconds; complete in two- 

 thirds in 30 minutes, and in five-sevenths in an hour. 



Reaction with Chromic Acid. 



V. sativa: Begins in all in 30 seconds; complete in all in 



5 minutes. 

 V. villosa: Begins in all in 45 seconds; complete in all in 



2J^ minutes. 

 V. faba: Begins in all in 30 to 60 seconds; complete in all 



in 3 minutes. 

 V. fulgens: Begins in all in 60 seconds; complete in all in 



2}^ minutes. 

 V. gerardi: Begins in all in 50 seconds; complete in all in 



80 seconds. 



Reaction with PyrogaUic Acid. 



V. saliva: Begins in all in 30 seconds; complete in all in 



5 minutes. 

 V. villosa: Begins in most in 15 seconds; complete in all 



in 114 minutes. 



of the Genus Vicia. — Continued. 



Effects of Various Reagents. — Continued. 

 Reaction with PyrogaUic Acid. — Continued. 



V. faba: Begins in a few seconds to 1}^ minutes; complete 



in ull in 6 minutes. 

 V.ftUgens: Begins in most in 15 seconds; complete in all 



in 1J4 minutes. 

 F. gerardi: Begins in all in 30 seconds; complete in all in 



1 }4 minutes. 



Reaction with Ferric Chloride. 



V. sativa: Begins in a few in a minute; complete in two- 

 fifths in 13 minutes; incomplete in all in an hour. 



V. villosa: Begins in a few in a minute; complete in nearly 

 all in 40 minutes. 



V. faba: Begins in a few in 1 Ji minutes; complete in two- 

 thirds in 50 minutes, but incomplete in all in an 

 hour. 



V. fulgens: Begins in a few in a minute; complete in 

 nearly all in an hour. 



V. gerardi: Begins in a few in 2 minutes; complete in 

 nearly all in three-fourths of an hour. 



Reaction with Purdy's Solution. 



V. sativa: Begins in some in 30 seconds; complete in one- 

 half and partial in one-fourth of the grains in 15 

 minutes. 



V. viUosa: Begins in some in a minute; complete in all in 

 20 minutes. 



V.faba: Begins in most in a minute; complete in nearly 

 all in 15 minutes. 



V. fulgens: Begins in nearly all in a minute; complete in 

 two-thirds and partial in one-third in 25 minutes. 



V. gerardi: Begins in nearly all in 1 minute; complete in 

 nearly all in 25 minutes. 



NOTES ON THE STARCHES OF VICIA. 



The Vicia starches show so close a corr&spondence in their histological properties and polari- 

 scopic reactions and in their reactions with iodine and the anilines that whatever differences exist 

 may fall within the limits of error, or at all events are insignificant. The differences in the temper- 

 atures of gelatinization are, however, quite marked, the lowest being 05° and the highest 72.5°, 

 those of V. sativa, V. fulgens, and V. gerardi being about the same (72.5°, 72°, and 71°), and those 

 of V. villosa and V. faba nearly the same (66° and 65°). With the chemical reagents the order of 

 sensitivity is different in the case of each starch with each reagent, making diagnosis easy. 



GENUS PHASEOLUS. 



The genus Phaseolus, which is so well known because of the large number of agricultural forms, 

 comprises about 60 well-defined species and perhaps over 100 garden and field varieties or forms. 

 Some botanists make many types and subtypes of the cultivated beans, but all may be resolved 

 into two fundamental types — the kidney-bean type, which is exemplified in the common kidney or 

 wax bean; and the sieva or civet-bean type, or the small, flat bean which is familiar in the Lima 

 beans. Representatives of these were examined in the form of the red kidney bean {Phaseolus 

 vulgaris Linn.), and Henderson's bush Lima bean (Phaseolus lunatus Linn.), both of which are 

 agricultural varieties. 



STARCH OF PHASEOLUS VULGARIS VAR. (RED KIDNEY BEAN). 

 (Plate 6, figs. 31 and 32. Chart 36.) 



Histological Characteristics. — In form the grains are simple, and are with a few exceptions 

 isolated. The surfaces of the grains are often somewhat irregular, owing to large rounded pro- 

 jections or to well-marked, sharp depressions. The conspicuous forms are ovoid, oval, elliptical, 

 reniform, and round; a few triangular forms have rounded corners and various modifications of the 

 foregoing. The grains are in many cases from one-half to two-thirds as thick as they are broad. 



