GENUS LACHENALIA. 



611 



are distinct. In the larger grains the hilum swells and the grain becomes covered with fine striae. 

 The inner portion is changed into a gelatinous mass, and the marginal part forms into a ring which 

 is irregular on its inner edge, striated, and marked by alternate refractive and non-refractive bands. 

 This ring becomes thinner and more transparent as the grain swells. The proximal end dissolves, 

 the contents of the capsule flow out and dissolve, followed by solution of the rest of the capsule. 

 The smaller grains begin to dissolve from the distal end before the hilum is affected, and the process 

 advances up the grain by fissuration and the breaking down of the starch into granules, which gran- 

 ules are transformed into a gelatinous mass, followed by solution. 



With -pyrogallic acid the reaction begins at once and gelatinization is complete in 40 seconds. 

 The process appeared to consist of a slow enlargement of the hilum without much change in the 

 grain, except that fine strise become evident throughout. Finally, a definite striated, banded ring 

 is formed at the margin and this becomes gradually clearer and transparent. The swollen grains 

 are not very large, are usually smooth, and not distorted, folded, or wrinkled. 



Reaction with ferric chloride begins in 30 seconds to a minute and is over in 20 minutes. 

 The hilum becomes prominent and swells, and the inner part of the grain is reduced to a gelatin- 

 ous mass. The ring formed at the margin is striated, but not distinctly banded. It becomes 

 thinner and clearer as the grain swells. The gelatinized grains are large, thin-walled, and not 

 much distorted or lobulated. Some grains begin to gelatinize at the distal end and the process 

 extends around the margin, followed by swelling of the hilum and subsequent changes the same as 

 those previously described. 



Reaction with Purdy's solution begins immediately in many grains. From one-fifth to one- 

 fourth are fully gelatinized in 2 hours and the rest are only partially gelatinized. The reaction 

 is the same as that with pyrogallic acid. 



Chart No. 183. 



P 1 GV T P 

 S 



CA PA FC P S CI PA CA 

 POPS 



STARCH OF LACHENALIA TRICOLOR VAR. LUTEOLA. (Plate 49, figs. 293 and 294. Chart 185.) 



Histological Characteristics.— In form the grains are simple, with the exception of a few compound 

 ones, which consist of two or more components. There are no aggregates, no well-defined pressure 

 facets, and very few clumps. The grains are rounded and the surface tends to be quite regular, 

 but a few irregularities are caused by the unequal devel- 

 opment of different parts of the surface. There are very 

 few of the nipple-like processes so common in L. pendula. 

 The conspicuous form is the oval, with the distal and 

 smaller end flattened. This form may be either short 

 and broad or long and slender. There are also ovoid, 

 round, pyriform, and ellipsoidal grains. Grains flattened 

 at the distal end have a cup-like depression in this part. 

 The grains when seen on end are round. 



The hilum is a very distinct, relatively large, round, 

 non-refractive spot, eccentric about one-fourth of the 

 longitudinal axis of the grain, and usually in the median 

 line. It is probably always a round cavity. It may be 

 fissured in the form of a narrow, short, transverse or 

 diagonal line; but fissuration is not common. 



The lamellce are usually fairly distinct, rather fine, 

 regular, continuous rings, or segments of rings or ellipses, 

 which follow the outline of the margin of the grain except 

 near the hilum. The lamellae near the cup-like depression, 

 sometimes observed in the distal end, often show a corre- 

 sponding curvature; those near the margin and distal end are larger, but not always more distinct 

 than those near the hilum. The former often appear to be separated from the latter by a very 

 distinct line, which may be either an elevation of the inner part of the grain or a distinct lamella. 

 There are about 2.5 lamellae on the medium-sized grains. 



The grains vary in size from 5 to SO/x. The common size is 22ju. 



Polarisco-pic Properties. — The figure is eccentric, distinct, clear-cut, and regular. Its lines 

 usually become broader and somewhat less distinctly outlined as they near the margin. The figure 

 is very regular in shape, usually in the form of a cross having the lines at right angles. 



Curve of Reaction-Intensities of Starch of Lachenalia 

 tricolor var. luteola. 



