GENUS BRODIiEA. 



595 



PC PS 

 5 



Reaction with pyrogaUic acid begins in 30 seconds, and is over in 2}/^ minutes; it is practically 

 the same as that of the grains of B. pedimcidaris. 



^A'ith ferric chloride there is some reaction in a minute. About half the grains are affected and 

 many completely gehitinizcd in 5 minutes. All but a very few are gelatinized in 30 minutes, and 

 all arc gelatinized in 40 minutes. The reaction in these grains is practically identical with that of 

 the gi-ains of B. peduncularis. 



With Purdy's solution there is a slight general reaction in a minute; two-thirds of the grains 

 are partly gelatinized in 20 minutes; none fully gelatinized. There is no further change in an 

 hour. The reaction is the same qualitatively as that of the grains of B. peduncular is. 



STARCH OF BRODI^A LAXA. (Plate 46, figs. 273 and 274. Chart 175.) 



Histological Characteristics. In form the grains are simple, except a few compounds which 

 consist of two or three components. There are a few aggregates of the smaller grains, and one or 

 more small grains may be seen fitting into a hollow or depression in a large grain, the exact lines of 

 demarcation between the adherent grains being very hard to distinguish. Twin grains also occur 

 which are united by some amorphous sul:)stance. Many grains show nipple-like processes or other 

 irregularities of the surface. The conspicuous forms are 

 the ovoid and oval; quadrangular, round, long and thin 

 ellipsoidal, and broad or short ellipsoidal forms are com- 

 monly seen; rarely there are triangular and long and thin 

 oval. The grains are not flattened in any diameter and 

 therefore seem round when viewed on end. 



The hilum is distinct and when not fissured it ap- 

 pears as a medium-sized round spot, eccentric about a 

 third of the longitudinal axis of the grain, usually in or 

 near the median line, rarely very much to one side. There 

 may be 2 or more hila, in pairs or irregularly, and each 

 may be surrounded by 2 or 3 lamella. The hilum is usu- 

 ally fissured. The fissures are commonly not deep or wide, 

 and they are usually very irregular and ragged. They are 

 commonly irregularly stellate, but 3- and 4-armed fissures 

 are frequently seen. Rarely the fissure is single, trans- 

 verse or diagonal, or with a double curve. It is not un- 

 common for a line of small, irregular fissm'es to extend 

 from the hilum in the longitudinal axis of the grain. 



The lamellce are fairly distinct and very coarse, 

 and more distinct near the margin than near the hilum. The difference in distinctness may be 

 because those near the hilum are more or less obscured by the fissures. They are quite regular 

 and tend to follow closely the line of the margin. Normally there are 6 to 8 lamellse on a medium- 

 sized grain. 



The grains vary in size from 3 to 40/r. The common size is 26ai. 



Polariscopic Properties. The figure is usually clear-cut and distinct, even to the edge of the 

 grain. Its lines are sometimes much bent and otherwise distorted, and do not always meet at the 

 hilum. 



The degree of polarization is high, not so high as that of the grains of B. peduncularis. It varies 

 somewhat in different grains and in different aspects of the same grain. 



With selenite the quadrants are usually clear-cut, irregular in shape, and unequal in size. The 

 colors are generally pure and bright; sometimes the yellow has an admixture of red. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains are colored deeply a blue- 

 violet; with 0.125 per cent solution the grains color deeply and the color deepens slowly. The 

 color is somewhat deeper than that of the grains of B. peduncularis. After heating until the grains 

 are completely gelatinized, the solution is colored slightly and the grains very deeply on the addition 

 of iodine. The grains are much swollen and lobulated. After boiling for 2 minutes the solution 

 is colored very deeply, but the grain-residues much less deeply or not at all. Most of the capsules 

 contain some blue-reacting starch in the proximal end and all show a red-violet coloration when 

 a slight excess of iodine is added. 



MINUTES 

 Curve of Reaction-Intensities of Starch of Brodiaea laxa. 



