RICHARDIA. 



721 



tal end, and ellipsoidal with one or more concavities at 

 the distal end. The conspicuous forms of the perma- 

 nently isolated grains are ellipsoidal, nearly round, and 

 round. The grains are not flattened excepting at the 

 pressure facets, as in-.fi!. albo-maculata. The forms of the 

 grains of the two parent species are closely alike, the 

 main differences being in the quantitative distribution 

 of the different kinds of grains. 



The hilum is frequently indistinct, but is demon- 

 strable in more grains than in R. albo-maculata, and is 

 a small, round, non-refractive spot, as in R. albo-maculata. 

 A small, rounded cavity is present at the hilum in more 

 grains than in R. albo-maculata, the hilum is more often 

 fissured than in R. albo-maculata, and the fissures are 

 short, and transverse, or cruciate, or Y-shaped. The 

 position of the hilum is centric in the majority of grains, 

 but it may have a range of eccentricity from 0.45 to 0.35, 

 rarely 0.25, of the longitudinal axis; there are somewhat 

 fewer grains with a centric hilum, and more with a slight 

 eccentricity than in R. albo-maculata. The main differ- 

 ences between the grains of the two species are in the 

 more frequent fissuration, the more frequent appearance 

 of the hilum, and the greater tendency to eccentricity of 

 the hilum in R. elliottiana. 



The lamella are frequently not demonstrable, al- 

 though they can be made out in more grains than in 

 R. albo-maculata. When observed they are found to be 

 of the same structure and arrangement as in R. albo- 

 maculata. The number can be determined more often 

 than in R. albo-maculata; that of the larger dome-shaped 

 component grains is usually 8, and on the larger perma- 

 nently isolated grains 12. The lamellae, while of the 

 same character and arrangement, are more numerous 

 in R. elliottiana. 



The size varies from the smaller grains which are 

 3 by 2/j., to the larger permanently isolated grains which 

 are 16 by 14/x, and the larger separated components which 

 are 22 by 22/i, in length and breadth. The common size 

 of the separated component grain is about 9 by 7/j,, and 

 of the permanently isolated grains 12 by 10/x. in length 

 and breadth. The size is slightly larger, on the whole, 

 than in R. albo-maculata. 



POLARISCOPIC PROPERTIES. 



The figure is usually centric to slightly eccentric, 

 rarely quite eccentric, and there are fewer of the centric 

 and more of the slightly eccentric figures than in R. albo- 

 maculata. The figure is distinct in the majority of 

 grains, but the lines are less often clear throughout the 

 entire figure than in R. albo-maculata. The lines are fine 

 in the majority of the grains, and intersect either at 

 right angles or obliquely, but they are quite broad in more 

 grains than in R. albo-maculata. They are generally 

 straight, often with broadening at the margin, but may 

 be bent and bisected as in R. albo-maculata. Double 

 and multiple figures are occasionally observed as in R. 

 albo-maculata. 



The degree of polarization is moderate to high (value 

 65), somewhat lower than in R. albo-maculata. It varies 

 in the different grains from moderate to high with more 

 of the former than in R. albo-maculata. The same vari- 

 ation is found in a given grain as in R. albo-maculata, 

 but the grains with one or more quadrants in which the 

 degree of polarization is low are more common. 



With selenite the quadrants in the majority of grains 

 are moderately clean-cut, sometimes quite clean-cut in the 

 larger permanently isolated grains; but there are fewer 

 grains in which the quadrants are clean-cut than in R. 

 albo-maculata. The quadrants are generally unequal in 

 size and slightly to quite irregular in shape. They are 

 unequal and irregular in considerably more grains than 

 in R. albo-maculata. The blue is pure in the majority 

 of grains, while the yellow is not usually pure. The 

 colors are less often pure than in R. albo-maculata. 



IODINE REACTIONS. 



With 0.25 per cent Lugol's solution the grains color a 

 moderate violet (value 40), which is redder in tint at 

 first, and after deepening very rapidly to about the 

 same depth it is still not so blue as in R. albo-maculata. 

 With 0.125 per cent Lugol's solution the grains color a 

 light violet of almost the same depth, but more reddish, 

 than in R. albo-maculata. After heating in water until 

 the grains are gelatinized and then adding 2 per cent 

 Lugol's solution they color a moderate to moderately 

 deep indigo-blue, somewhat more grains of the former 

 and hence lighter than in R. albo-maculata; the solution 

 colors a moderately deep indigo-blue as in R. albo-macu- 

 lata. If the preparation is boiled for 2 minutes, and 

 then treated with an excess of 2 per cent Lugol's solution, 

 the grain-residues become a light to moderate blue with 

 majority of the former, and in most of them with reddish 

 tint, the color being lighter than in R. albo-maculata; 

 most of the capsules color an old-rose, and a few a wine- 

 red color, and they are lighter and somewhat redder than 

 in R. albo-maculata. The solution is a deep indigo- 

 blue as in R. albo-maculata. 



ANILINE REACTIONS. 



With gentian violet the grains color faintly at once, 

 and in half an hour they are lightly stained (value 33), 

 but slightly deeper than in R. albo-maculata. 



With safranin the grains color very lightly at once, 

 and in half an hour they are lightly colored (value 35), 

 slightly deeper than in R. albo-maculata. The grains 

 color a little deeper with safranin than with gentian 

 violet, as in R. albo-maculata. 



TEMPERATURE REACTIONS. 



The majority of the grains are gelatinized at 74 

 to 75 C., and all at 76 to 77 C., mean 76.5 C. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins immediately. 

 Complete gelatinization occurs in about 83 per cent of the 

 entire number of grains and 92 per cent of the total starch 

 in 3 minutes; in about 90 per cent of the grains and 

 97 per cent of the total starch in 5 minutes. (Chart 

 D 545.) 



The hilum becomes moderately distinct, and a bubble 

 is occasionally formed there. In some grains, also lines 

 or canals leading from the hilum to the distal corners of 

 the pressure facets may be seen. No lamella? are visible. 

 A narrow refractive band is formed slowly about the 

 margin of the more resistant grains. Gelatinization be- 

 gins in the small grains and in many of the larger grains 

 in all parts at once ; in a few of the more resistant grains, 

 at the corners of the pressure facets; and in most of 

 the rest, at one distal corner or at the proximal end, in 



