GENUS ORNITHOGALUM. 



555 



Chart No. 149. 



GENUS ORNITHOGALUM. 



The genus Ornithogalum, which is one of the largest of the Liliacece, comprises about 100 species 

 grouped among 7 subgenera. They are bulbous plants widely distributed over Europe, Africa, and 

 the Orient. Some species have been introduced into America for garden cultivation, and some 

 hardy kinds are found gi-owing wild. 0. umbellatum is popularly known as the star of Bethlehem. 

 Two species and two varieties were studied as types of the genus: 0. nutans Linn., 0. umbellatum 

 Linn., 0. narhonense (pyramidale) Linn., and 0. Ihijrsoides var. aureum Ait. (0. aureum Curt.). 



STARCH OF ORNITHOGALUM NUTANS. (Plate 37, figs. 221 and 222. Chart 149.) 



Histological Characteristics. Inform the grains are simple, and they are isolated, with the excep- 

 tion of rare doublets. There are no chnnps and no i^ressure facets were observed on the isolated 

 grains. The surface of some of the grains is somewhat irregular, owing to the addition of sets of 

 lamellae whose longitudinal axes do not coincide with the 

 axis of the larger part of the grain. These sets of lamellae 

 were probably added at different periods of growth of the 

 grain. As a rule, the grains are quite regular in outline. 

 The conspicuous forms are the rounded ovoid and ovoid. 

 The latter may have a narrow and squared distal end with 

 a small depression in the middle of the squared portion. 

 In addition, there are spherical, short elliptical, quadran- 

 gular with very rounded corners, and irregular forms. 

 The grains are not flattened and are as thick as they are 

 broad, and hence appear spherical when seen on end. 



The hilum is a fairly distinct, small to comparatively 

 large, round or rarely lenticular spot, eccentric about one- 

 third or more of the longitudinal axis, and in the median 

 line. In small grains it may be centric. There are, rarely, 

 2 or more hi) a in a single grain. The hilum sometimes has 

 a fissure, which is usually a small, single, clean-cut trans- 

 verse or diagonal line ; or there may be a cross or an irreg- 

 ularly stellate arrangement of small fissures. 



The lamellce are fairly distinct, usually regular, rather 

 coarse rings. They are continuous, except those near the distal end, at which point there may be 

 a set of chscontinuous lamellae, the longitudinal axis of which does not coincide with that of the body 

 of the grain. They are usually coarser and more distinct near the margin and at the distal end than 

 near the hilum. There are 10 to 13 lamellae on the larger grains. 



The grains vary in size from 6 to 38^. The common size is 26/i. 



Polariscopic Properties. The figure is almost invariably eccentric, distinct, fairly clear-cut, 

 and fairly regular. The lines are broad, and become broader, but less clearly outlined near the 

 margin. They are usually straight and sometimes placed at equal angles to one another, and they 

 are occasionally bisected. 



The degi-ee of polarization is high. It does not vary much in different grains, nor in different 

 aspects of the same grain. 



With selenite the quadrants are usually well defined, fairly regular in shape, and unequal in 

 size. The colors are pure. 



Iodine Reactions. With 0.25 per cent Lugol's solution the grains color a fairly deep blue- 

 violet; with 0.125 per cent solution they color rather lightly and the color deepens fairl}' rapidly. 

 After heating in water until all the grains are completelj^ gelatinized, the solution colors lightly 

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

 and most of the grain-residues color deeplj'. Some of the capsules color violet with excess of iodine, 

 the color of the others being obscured by the large amount of blue-reacting starch retained by them. 



Staining Reactions. With gentian violet the grains begin to stain at once and in 30 minutes 

 are deeply stained, some more than others. 



With safranin the grains begin to stain deeply at once and in 30 minutes are very deeply stained, 

 one as much as another. 



Temperature Reaction. The temperature of gelatinization is 60.5 to 62 C, mean 61.25. 



Curve of Reaction-Intensities of Starch of OrnitKogalum 



nutans. 



