GENUS LATHTRUS. 



399 



Chart No. 43. 



GV S T CI CA PA FC P S CI PA CA 



Curve of Reaction-Intensities of Starch of 

 Lathyrus latifolius var. albus. 



scctimi of the lines. In the elongated forms it may be in tiic form of a cross or of the bean tj-pe a 

 longitudinal line \\nth bisected ends. The lines are broad, usually straight, but not as a rule clear-cut. 



The degree of polarization is low to high, usually fairly high. It does not vary much in differ- 

 ent aspects of a grain. Areas in which there is an absence of polarization are common in the central 

 l)arts of grains and in some grains only very small marginal parts transmit light. Polarization is 

 less than in L. odoratits var. shahzada. 



With selenite the quadrants are usually not well 

 defined, are generally irregular in form and mieqiial in 

 .''ize, and often subdivided. The colors are fairly pure. 



Iodine Reactions. With 0.25 per cent Lugol's solu- 

 tion the grains all color a fairly deep blue-violet; with 

 0.125 per cent solution they color rather lightly and the 

 color deepens fairly rapidly. It is darker than in L. 

 odoratus var. shahzada. After heating in water until the 

 grains are completely gelatinized, the solution colors 

 deeply and the majority of the gelatinized grains very 

 slightly on the addition of iodine. After boiling for 2 

 minutes the solution colors deeply, but only an occasional 

 grain-residue is colored, probably 1 in 1,000. When an 

 excess of iodine is added the capsules color a bright blue, 

 probably because of the retention of a small amount of 

 blue-reacting starch, but bj- a further addition they be- 

 come a deep reddish-\nolet. 



Staining Reactions. With gentian violet and with 

 safranin the grains when viewed in masses show a very 

 slight tint of violet, and after remaining in the solution for 30 minutes they are very lightly 

 stained. The coloration is the same as in the grains of L. odoratus var. shahzada. 



Temperature Reaction. The temperature of gelatinization is 02 to 04 C, mean 03. 



Effects of Various Reagents. With chloral hydrate-iodine reaction begins at once. A few grains 

 are gelatinized in a minute, about two-thirds in 5 minutes, five-sixths in 15 minutes, nine-tenths in 

 30 minutes, with slight progress in an hour. The gelatinizeil grain is rather more irregular in out- 

 line than in L. odoratus var. shahzada, owing to the frequent formation of protuberances during 

 gelatinization; otherwise the reaction is qualitatively the same as in L. odoratus var. shahzada. 



The grains begin to react at once with chromic acid. A few are dissolved in 30 seconds and all 

 in SK minutes. The outlines of the grains during the reaction are more irregular than in L. odoratus 

 var. shahzada; otherwise the reaction is the same. 



AVith pyrogallic acid the grains begin to react at once. A few are gelatinized in 30 seconds and 

 all in 2 minutes. More of the gelatinized grains break up than in L. odoratus var. shahzada. The 

 reaction is qualitatively the same as in the latter. 



Reaction with feiric chloride liegins in a minute. A few grains are gelatinized in 3 minutes, 

 one-fifth in 15 minutes, one-third in 30 minutes, and about nine-tenths in an hour. The reaction 

 is qualitatively the same as in L. odoratus var. shahzada. 



The grains begin to react at once with Purdy's solution. A few are gelatinized in a minute, 

 more than half in minutes, about two-thirds in 15 minutes, and nearly all are partially or com- 

 pletely gelatinized in 30 minutes. There is little if any further change in an hour. The reaction 

 is qualitatively the same as in the gi-ains of L. odoratus var. shahzada. 



STARCH OF LATHYRUS MAGELLANICUS VAR. ALBUS. (Plate 8, figs. 45 and 46. Chart 44.) 



Histological Characteristics. In form the grains are simple and isolated, and a large propor- 

 tion are deeply fissured. In some grains there is a central, clean-cut or ragged fissure; in others 

 there are two or more deep fi.ssures; in others a comljination of deep fissures arranged in a ring 

 incloses a central area; in others the fissiu-es are numerous and irregularly disseminated. The sur- 

 face of the grains is quite irregular, distinctly more so than in the other Lathyrus starches. The 

 conspicuous forms are the ovoid, oval, nc^arly round, pyriform, triangular, and quadrangular with 

 well-rounded corners and reniform, all of which are more or less irregular. There are also grains 

 of various irregular shapes. Tlie grains are not so thick as they are broad. 



