GENUS BRODL^A. 



601 



With safranin the grains stain immediately and after 30 minutes they are fairlj' deeply stained, 

 much more than B. pcduncularis. These grains are more evenly stained than those of the other 

 Brodiara starches. 



Tctiipcrature Reaction. The temperature of gelatinization is 66 to 68 C, mean 67. 



Effects of Various Reagents. With chloral hydrate-iodine a few grains show signs of reaction 

 in 2 minutes, about one-fifth in 5 minutes, about one-third in 10 minutes, and about two-thirds 

 in 30 minutes. About three-fourths have fully reacted in IJ2 hours, but the others are unaf- 

 fected. There is no further change. The reaction is qualitatively the same as that of the grains 

 of B. peduncularis. 



Reaction with chromic acid begins in some grains in 30 seconds and is general in IJ^ minutes. 

 It is over in 10 minutes, and it agrees qualitativelj' in every respect with that of the grains of B. 

 peduncidaris. 



There is reaction with pyrogallic acid in a few grains in a minute and it is general in 5 minutes. 

 About one-third to one-half arc partially gelatinized in 25 minutes, and the reaction has practic- 

 ally reached its limit in 35 minutes, at which time some of the grains show the beginning of reaction, 

 while others are in all transitional stages between beginning and completion. There is no further 

 change. The reaction is qualitatively the same as that of the grains of B. peduncularis. 



With /e?Tic chloride some grains show a slight reaction in 1}^ minutes. About one-fifth are 

 afi'ected in 5 minutes, half in 10 minutes, and two-thirds in 20 minutes. Practically all are com- 

 pletely gelatinized in an hour. The reaction is quahtativelj' the same as that of the grains of B. 

 peduncularis. 



There is reaction with Purdy's solution in some grains in 5 minutes. About one-fourth show 

 signs of reacting in an hour and about three-fourths in 1 J^ hoins, but only a few are completely gela- 

 tinized within this time. There is no further change. The reaction, as far as it goes, is qualita- 

 tively the same as tliat of the grains of B. peduncularis. 



STARCH OF BRODI^A STELLARIS. (Plate 48, figs. 283 and 284. Chart 180.) 



Histological Characteristics. In form the grains are simple, with the exception of a few com- 

 pomid grains. There are a few small aggregates among the smaller grains and also among some 

 larger grains which have two or three small grains adherent to the surface. There are no pressure 

 facets. The surface tends to be irregular, owing to irreg- 

 ularities of development, chiefly in the form of large or 

 small nipple-like processes and rounded projections which 

 give an uneven margin to an otherwise regular form. The 

 conspicuous forms are the ovoid, oval, and ellipsoidal; also 

 pyriform, elliptical and round, and many irregular forms. 

 The grains, as a rule, are not so irregular in outline as 

 those of B. peduncularis. Rarely grains occur with a 

 mass of amorphous accretions, usually attached to the 

 distal end. 



WTien the hilum is not fissured it is a fairly distinct, 

 comparatively small round spot situated eccentrically 

 about one-ttiird of the longitudinal axis of the grain, 

 usually in or near the median line. There are rarely 2 

 hila; a larger number was not observed. The hilum is 

 generally fissured, but the fissures are not particularly 

 broad or long. The common forms are simple trans- 

 verse, 3-armed, or 4-armed. The lines may be straight or 

 curved. Frequently the fissure presents a double curve. 

 The fissures are, as a rule, clean-cut and not ragged. 



The lamellw are distinct and rather coarse, especially one or two near the margin. They are 

 regular, continuous, and follow closely the outline of the margin except when the latter is distorted 

 by irregular projections of an amorphous character. They sometimes show waviness and bending 

 not related to the outline of the margin. There are 12 to 18 lamellae on the medium-sized and large 

 grains. 



The grains vary in size from 2 to 40;^. The common size is 22fi. 



Curve of Reaction-Intensities of Starch of Broc]ieea 

 stellaris. 



