GENUS HEDYCHIUM. 



787 



Chart No. 328. 



GENUS HEDYCHIUM. 



This genus includes about 25 species of rhizomatous plants, natives of tropical Asia, many of 

 them being found in India. Some are in cultivation, chiefly as green-house plants, and are popularly 

 knowni as the garland flower, the butterfly lily, and the ginger lily. Starches from 2 species, 

 both natives of India, were studied: H. coronarium Kocnig and H. gardnerianum Roscoe. The 

 starch of the latter we were not able to free entirely from foreign matter. 



STARCH OF HEDYCHIUM CORONARIUM. (Plate 81, figs. 483 and 484. Chart 328.) 



Histological Chamderistics. Inform the grains are simple, with the exception of rare compound 

 grains of two components. There are no aggregates and no pressure facets, and there are few clumps. 

 The surface is rounded, and tends to an irregularity of outline, owing chiefly to nipple-like projec- 

 tions, especially at the proximal end. The conspicuous form is that of a flattened ellipse with 

 the pointed proximal end which is usually bent laterally; also triangular, spindle-shaped, pyriform, 

 nearly circular, approaching the clam-shell type, and various irregular forms. The grains generally 

 tend to be more or less bent along the longitudinal axis, especially the proximal end; many exhibit 

 the effects of erosion of the proximal end, which may be 

 very limited or extend to or beyond the middle. The 

 grains are distinctly flattened, being about one-fourth 

 as thick as broad. When on edge they are very slender 

 and spindle-shaped, and often curved and irregular. 



The hilum is always invisible in the simple grains, 

 probablj^ because it is situated at the extreme tip of the 

 pointed projection of the end of the grain. In some of 

 the rare compound grains a small, round, indistinct hilum 

 may be seen in the median line in each of the two parts of 

 the grain. The hilum in these grains is extremely eccentric. 



The lamellw are distinct, fine, regular arcs of circles, 

 probably continuous. They follow closely the outline of 

 the distal end. They vary much in distinctness, those 

 at the distal end generally ajjpearing to be the most 

 distinct and the coarsest. There are about 58 to 60 on 

 the larger grains. 



The grains vary in size from 8 to 62;u. The dimen- 

 sions of the most conspicuous grains average about 48 

 by 20ai. The common length is about 42^. 



Polariscopic Properties. ^The figure is extremely eccentric, fairly distinct, but not clear-cut. 

 Usually only one line of the figure is seen, occasionally two. The lines are broad and not sharply 

 defined, and in some grains are joined by a cross-line at about two-thirds of the distance from the 

 hilum to the distal end. 



The degree of polarization is low. It varies in different grains and even in different parts of 

 the same grain, and according to the aspect of the grain. When the grains are viewed on end or on 

 edge, polarization is quite high. 



With selenite the quadrants are not well defined, are irregular in shape, and unequal in size. 

 The colors are not pure. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains color at once a bluish-violet 

 fairly well; with 0.125 per cent solution the grains color lightly at first, and then slowly deeper. 

 After heating in water until the grains are completely gelatinized, the solution colors deeply and 

 the grains deeply to very deeply on the addition of iodine. After boiling for 2 minutes, the solution 

 colors much more deeply and the grain-residues somewhat less. The grains are much swollen and 

 distorted, and with an excess of iodine many of the more lightly colored show a dark-violet capsule. 



Staining Reactions. With gentian violet and with safranin the grains begin to stain at once and 

 after 30 minutes are deeply stained. 



Temperature Reaction. The temperature of gelatinization is 71.5 to 73.1 C, mean 72.3. 



Effects of Various ReagenU. With chloral hydrate-iodine reaction begins in most grains in 

 30 seconds; most arc darkened in 5 minutes, and all in 10 minutes, and the reaction is complete 



Curve of Reaction-Intensities of Starch of Hedycliium 

 coronarium. 



