GENERA AMARYLLIS AND HIPPEA8TRUM. 627 



ward and collapses, and the grain invaginates at the proximal end, and then protrudes after the 

 disappearance of the bubble. Gelatinization proceeds rapidly along the course of the two radiating 

 fissures or rarely a single central fissure, with their many lateral branches, until it reaches nearly 

 to the distal end, which is much more resistant than the other part of the grain. Refractive granules, 

 which are finally gelatinized, are sometimes observed as the lamellae become gelatinized. The 

 gelatinized grain is much swollen and usually rounded at the proximal end, but thrown into many 

 folds at the distal end, so that it does not resemble in form the untreated grain. 



Reaction with ferric chloride begins in a minute. A few grains are gelatinized in 2)^ minutes, 

 nearly all in 10 minutes, and all but rare resistant grains in 15 minutes. The reaction is complete 

 in practically all in 20 minutes. A very exceptional grain may resist the reagent for 30 minutes. 

 The hilum, or the cleft located at the hilum, becomes very distinct, and a transparent border is formed 

 around a central opaque portion of the grain. In the border the lamella; become sharply defined 

 and striated, and the area gradually increases in width, followed by gradual complete gelatiniza- 

 tion at the hilum. A bubble frequently appears at the hilum, and enlarges and collapses, and just 

 as it collapses the proximal end or sides nearby are temporarily invaginated. A short, transverse 

 fissure usually appears within the capsule at the region of the hilum, and gelatinization begins 

 at this point, accompanied by rapid distension of the capsule. In grains with prominent corners 

 or protuberances gelatinization begins simultaneously at these points and at the proximal end, or 

 at the latter a little later. In many grains gelatinization proceeds gradually from the proximal to the 

 distal end, which latter is the last to undergo the reaction. In some grains a transverse fissure similar 

 to that observed at the hilum appears within the capsule near the distal end, followed by gelatiniza- 

 tion and distension of capsule at the distal end. The two centers of gelatinization then advance 

 towards each other, the central part of the grain being the last to undergo gelatinization. The most 

 resistant starch is generally broken into fairly large granules which later are gelatinized separately. 



With Purdy's solution the reaction begins immediately. A few small grains are gelatinized 

 in 30 seconds and about two-thirds of the grains are completely gelatinized in 2 minutes. All of 

 the remaining one-third are gelatinized, except a small cap-like portion at the distal end of each 

 grain, which is much more resistant than other parts of the grain, and this disappears except 

 in rare resistant grains in 10 minutes. The reaction is usually complete in all of the grains in 15 

 minutes; rarely a resistant grain lasts for 30 minutes. At the hilum a bubble is usually formed 

 which enlarges, then collapses, followed by rapid gelatinization of the grain and distension of the 

 capsule at the proximal end. Gelatinization proceeds rapidly until all but a small, cap-like portion 

 is reached at the distal end which is generally much more resistant than the other part of the grain. 

 Rarely gelatinization starts at the distal end a little later than at the proximal end, and the two 

 areas of gelatinization advance towards the middle of the grain. The center of gelatinization at 

 the distal end may be in a secondary set of lamellae which sometimes appears to inclose the primary 

 set. The stages of the reaction are similar to those noted for pyrogallic acid. 



GENUS HIPPEASTRUM. 



This genus includes 40 to 50 species of bulbous plants, natives of tropical America. The genus 

 is closely allied to certain other members of Amaryllidaceoe studied in this research (see page 625), 

 and most of them are cultivated under the name of Amaryllis. They are popularly known as the 

 knight's star lily, equestrian star, and as other forms of lilies. Starches from two species and one 

 horticultural variety were studied as types of the genus: H. vittatum Herb., the most common species 

 in cultivation in our gardens, is a native of Peru; H. equeslre Herb., known as the Barbados lily, 

 is a native of Mexico, Chile, and Brazil; and H. aulicum var. robustum Hort., is from a parent species 

 that is a native of Brazil and known as the hly-of-the-palace. 



STARCH OF HIPPEASTRUM VITTATUM. (Plate 52, figs. 307 and 308. Chart 208.) 



Histological Characteristics. — In forfn the grains are usually simple. Compound grains and 

 aggregates, each generally in the form of two components, are occasionally observed. Some of 

 the latter consist of a large grain with a small grain, which appears in the form of a large, nodular 

 projection. No pressure facets were seen on the isolated grains, and no clumps were noted. The 

 surface of the grains is somewhat irregular owing to irregularities in development, chiefly in the 

 form of an addition at different periods of two or three or more discontinuous lamelliP, to nipple- 

 like processes. The conspicuous forms ai-e the spherical ovoid, ovoid with a pointed distal end, 



