576 



STARCHES OP LILIACEiE. 



GENUS GALTONIA. 



This genus consists of three species of hardy, bulbous plants, native of the Cape of Good Hope, 

 and known as giant summer hyacintlis. The genus differs from Hyadnthus chiefly by the larger 

 number and the flattened character of the seeds. G. candicans Decne. (Hyadnthus candicans 

 Baker), the best-known species, was used as the source of starch. 



STARCH OF GALTONIA CANDICANS. (Plate 42, figs. 247 and 248. Chart 162.) 



Histological Characteristics. — Inform the grains are both simple and compound, the latter being 

 double and multiple. There are a great many aggregates, and among them triplets and multiples 

 are frequently observed. No pressure facets were found on the isolated grains. There are very 

 few small clumps. The surface is often very irregular and quite varied, due in part to the presence 

 of protuberances, rounded or nipple-like, either at the distal or proximal end, or both; and also 

 in part to lamellated additions of varying sizes to the sides or at the distal end, these additions 

 forming an angle with the longitudinal axis of the grain. Owing to the latter a primary oval grain 

 is frequently transformed into a triangular form with rounded angles, or into some irregular form. 

 Furthermore, sometimes there are irregular depressions on the margin of the grain. The multiple 

 grains are often triangular with rounded angles, and may 

 also have irregular depressions and projections; the trip- 

 lets have usually a roimded triangular form. The con- 

 spicuous forms of the simple grains are rounded oval, 

 ovoid, elongated ovoid, rounded oval at the proximal end 

 and elongated and flattened at the distal end, pyriform, 

 ellipsoidal, round, broadened, and elongated, mussel- 

 shell-shaped, and various irregular forms. 



The hilum is a fairly large round or oval spot, centric 

 in the round forms, and usually eccentric two-fifths to 

 one-sixth, generally one-third, in the other forms. There 

 are 2, and often more, hila in a single grain. The hilum 

 usually is not fissured. Rarely one or more fissures are 

 found which are often ragged; also occasionally an irreg- 

 ular cavity may be seen at the hilum. 



The lameUoe are distinct, rather coarse, complete 

 rings or ellipses around the hilum. They are finer, and 

 probably incomplete, near the distal margin, towards 

 which end they assume the shape of the grain and are 

 often quite irregular. Some forms have an especially dis- 

 tinct lamella at about one-half or one-third of the distance between the hilum and distal end. 

 are 12 to 14 lamellae in the larger grains. 



The grains are 5 to 74/i in size. The common size is 39 by 26/* in length and breadth. The large 

 round forms are about 34/*. 



Polariscopic Properties. — The figure is eccentric, distinct, and fairly clear-cut. In some forms 

 the lines are thick, generally more or less distorted by bends, variations in width, and bisection. 



The degree of polarization is high. It is variable, ranging from very high in the largest forms 

 to fair in the smallest grains. It often varies in the same aspect of a given grain. 



With selenite the quadrants are fairly well defined, generally very irregular in shape, and unequal 

 in size. In most of the grains the colors are bright and pure, but in some there is a greenish tinge. 



Iodine Reactions. — With 0.25 per cent Lugol's solution the grains color a deep indigo; with 

 0.125 per cent solution they color fairly and the color deepens rapidly. After heating in water until 

 all the grains are completely gelatinized, the solution colors fairly deeply and the swollen grains 

 deeply on the addition of iodine. After boiling for 2 minutes the solution colors very deeply and 

 the grain-residues lightly or not at all. With an excess of iodine all the capsules color violet with 

 a distinct tinge of red. 



Staining Reactions. — With gentian violet the grains begin to stain lightly at once and in 30 min- 

 utes they are lightly stained. 



With safranin the grains begin to stain at once and in 30 minutes they are fairly stained. 



Temperature Reaction. — ^I'he temperature of gelatinization is 57.8° to 59.5° C, mean 58.65°. 



Curve of Reaction-Intensities of Starch of Galtonia 

 candicans. 



There 



