GENUS HIPPEASTRUM. 629 



starch forms a thick, coarsely striated, marginal ring consisting of alternate refractive and non- 

 refractive bands. In some grains there is not only a complete marginal ring, but one or two or 

 more concentric segments of rings at the distal end. The grains continue to swell until they are 

 very large, and the marginal ring becomes thin and transparent and is finally dissolved at some 

 point, usually near the proximal end. The inner, gelatinized starch flows out and is dissolved, 

 followed by solution of the rest of the marginal ring or capsule. 



With pyrogaUic acid reaction begins in some grains in 30 seconds and in all in a minute. About 

 three-fourths of the grains are gelatinized in 7 minutes and almost all in 30 minutes. The hilum 

 begins to swell, and a bubble is formed there which increases, then decreases in size, and finally 

 disappears. The grain is marked by coarse strise, and the less resistant starch is converted slowly 

 into a gelatinous mass which occupies the cavity made at the hilum, which mass, by swelling, pushes 

 the more resistant starch to the margin, where a thick, coarsely striated ring is formed that shows 

 alternate refractive and non-refractive bands. This ring becomes somewhat thinner and transparent 

 as the grain swells. The swollen grains are large, distorted, wrinkled, and crumpled, and do not 

 retain the original form of the grain. 



Reaction with ferric chloride begins in a few grains in a minute. It is over in half the grains 

 in 12 minutes, in nearly all in 25 minutes, and in all in 55 minutes. The reaction begins in the small 

 grains at the hilum, which swells, and the grain becomes covered by fine radial strise. The interior 

 of the grain is converted into a gelatinous mass, leaving a broad, dense, finely striated ring at the 

 periphery, which becomes thin and transparent. In the larger grains the reaction begins at the distal 

 end, which is first fissured and then becomes gelatinous, and this gelatinization proceeds upward 

 over the rest of the grain. The resulting gelatinized grains are large, wrinkled, and somewhat 

 distorted. 



The reaction with Purdy's solution begins in some grains in a minute and in most grains in 2 

 minutes. About one-fifth are partially gelatinized in 10 minutes, a third are partially and a few 

 completely gelatinized in 40 minutes, and one-third are completely gelatinized in \]/2 hours. The 

 reaction is qualitatively the same as that with pyrogallic acid. 



STARCH OF HIPPEASTRUM EQUESTRE. (Plate 52, figs. 309 and 310. Chart 209.) 



Histological Characteristics. In form the grains are usually simple, compound grains are not 

 common, and there are a few small aggregates. No pressure facets are observed on the grains. 

 There were no clumps. The surface tends to be somewhat irregular, owing to the unequal develop- 

 ment, and but rarely to lamellated depositions at different periods of growth and nipple-like processes. 

 The conspicuous forms are the ovoid, which may be broad and almost spherical, or narrow and with a 

 pointed distal end; eUiptical with rounded ends of about equal size; triangular and quadrangular 

 grains wth rounded corners, reniform, spherical, lenticular, and pjTiform grains. The grains are 

 rarely flattened, and therefore nearly always as thick as they are broad. Some of the large grains 

 are about two-fifths to a half as thick as broad. 



The hilum is a distinct, fairly large, round or lenticular spot, usually eccentric about one-third 

 to two-fifths of the longitudinal axis, and in or to one side of the median line. There may be 2 or 

 more hila in a single grain. The hilum is often fissured, and the fissure is usually single, short, and 

 narrow, but ragged and irregular. There may be two clear-cut fissures arranged as a cross. 



The lamellcB are fairly distinct, rather coarse, irregular, continuous or discontinuous rings which 

 are usually coarser and more distinct near the margin than near the hilum. They vary very much 

 in distinctness in different grains. There is often one very distinct lamella separating the less coarse 

 lamellae about the hilum from the coarser ones beyond, and it may represent the outline of a primary 

 grain. There are 6 to 8 lamella? on the larger grains. 



The grains vary in size from 4 to 35^. The common size is 20|i. 



Polariscopic Properties. The figure is usually eccentric, distinct, sometimes not clear-cut, 

 and irregular. The lines are thick and thicker marginally, and often slightly bent and otherwise 

 distorted, and placed at varjing angles to one another. 



The degree of polarization is fairly high. It varies in different grains, in different aspects of 

 the same grain, and in different parts of the same aspect of a given grain. It is not so high as that 

 of the grains of H. vittatum. 



With selenite the quadrants are not, as a rule, sharply defined and are irregular in shape and 

 unequal in size. The colors are not so bright as in H. vittatum, and usually not quite pure. 



