412 



STARCHES OF LEGUMINOS^. 



Differentialion of Certain Starches of the Genus Pisum. Continued. 



Effects of Various Reagents. Continued. 

 Reaction with Pyrogallie Acid. 



Eugenie (green): Begins in some at once; all slightly 



affected and a few gelatinized in 2 minutes; very 



little change after an hour. 

 Eugenie (yellow): Begins in some at once; all affected 



and a few gelatinized in 2} 2 minutes; very little 



change after an hour. 

 Thomas Laxlon: Begin.s in some at once; all affected in 



5 minutes; very little change in an hour. 

 Electric Extra Early: Begins in all at once; complete in 



most in 2J2 minutes, in all in 4 minutes. 

 Mammoth Grey Seeded: Begins in all at once; complete 



in all in 3 minutes. 

 Large White Marrowfat: Begins in all at once; complete 



in all in 2 minutes. 



Reaction with Ferric Chloride. 



Eugenie (green): Begins in all in 30 seconds; complete 



in nearly all in 30 minutes. 

 Eugenie (yellow): Begins in all in 30 seconds; same as 



Eugenie (green). 



Effects of Various Reagents. Continued. 

 Reaction with Ferric Chloride. Continued. 



Thomas Laxton: Begins in all in a minute; complete in 

 nearly all in 30 minutes; incomplete in an hour. 



Electric Extra Early: Begins in all in 30 seconds; com- 

 plete in one-si.\th in an hour. 



Mammoth Grey Seeded: Begins in all in a minute; com- 

 plete in one-sixth in an hour. 



Large White Marrojvfol: Begin.s in all in 30 seconds; com- 

 plete in one-fourth in an hour. 



Purdy's Soluiio?i. 



Eugenie (green): Begins in some in 30 seconds; all nearly 

 completely gelatinized in 30 minutes. 



Eugenie (yellow): Begins in some in 30 seconds; same as 

 Eugenie (green). 



Thomas Laxton: Begins in some at once ; same as in Eugenie 

 (green). 



Electric Extra Early: Begins in some in 30 seconds; com- 

 plete in two-thirds in an hour. 



Mammoth Grey Seeded: Begins in some in 30 seconds; 

 complete in one-third in an hour. 



Large White Marrowfat: Begins in some in 30 seconds; 

 complete in nine-tenths in 30 minutes. 



NOTES ON THE STARCHES OF PISUM. 



The members of Pisu7n may be grouped in accordance with the pecuharities of the seeds into 

 the vrrinkled, smooth, and indent, and further distinguished by color, sweetness, and other incidental 

 properties. The six specimens of starches studied were prepared from five garden varieties two 

 wrinkled, one smooth, and two indent forms. Upon examination of text and photographic data 

 it will be seen that there are two conspicuous types of starch-grains present those of the rosette 

 type and those of the bean type and that in the Eugenie and Thomas Laxton peas, which are 

 of the wTinkled kind, the starch is typically of the rosette tjT3e, with very few grains of the bean 

 type; while in the Electric Extra Early and Mammoth Grey Seeded, both indent peas, and in the 

 Large White Marrowfat, a smooth pea, the grains are of the bean type. These differences in the 

 starch-grains, coupled with peculiarities of the surface of the seeds, were so striking as to have led to 

 an examination of a number of garden varieties to determine if all wrinkled peas are characterized 

 by the rosette type and all smooth and indent peas by the bean type. The following were selected 

 for comparison in addition to those named: 



Wrinkled: Heroine, Surprise, Early Morn, Sutton's Excelsior, Admiral Dewey, Gradus. 



Smooth: Alaska, Black Eyed Marrowfat, Tall White Sugar. 



Indent: Lightning, Small P>en(^h Canner, Extra Early Pioneer, Giant Sugar, Blue Imperial, Eai'ly June, 



Bountifully Early, Michell's Special Extra Early, Dandy Extra Early, Eureka Extra Early. 

 Smooth, Inderd, and Wrinkled, Vilmorin Marrow. 



It was found in all of the wrinkled peas that the starch is of the rosette type; in the smooth 

 and indent peas, of the bean type; and in the Vilmorin Marrow, which was made up of a mixture 

 of the three kinds of seeds, that there was mixture of the rosette type and bean type, and that 

 those of the first type were derived from the wrinkled seeds. This differentiation is most striking. 

 Verj' interesting results have been recorded by Gregory (Part I, page 72) on the effects of 

 hybridization in case of peas bearing seeds distinguished by having these different types of grains. 



The green and yellow Eugenie seeds do not, as might be expected, show any marked differences 

 in either their histological properties or reactions, the only noticeable variations being shown by 

 the green-pea starch having a slightly lower polarization, a lower temperature of gelatinization (1), a 

 greater sensitiveness to chromic acid, and slightly more sensitivity to pyrogallie acid. The close cor- 

 respondences of the starch of the Thomas Laxton variety to the Eugenie starch are as marked as those 

 between the green and yellow Eugenie seeds, suggesting extremely close botanical forms of plants. 

 The likenesses of the starches of the second group (the round and indent peas) is equally marked. 

 These starches are readilj' distinguished from those of the first group (wrinkled peas) by the bean 

 type of grains, the distinctly higher degree of polarization, the more marked iodine and aniline reac- 

 tions, the lower temperature of gelatinization, the less sensitivity to chloral hydrate-iodine, a much 

 greater sensitivity to pyrogallie acid, and the less sensitivity to ferric chloride and Purdy's solution. 



