664 



DATA OF PROPERTIES OF STARCHES OF PARENT- AND HYBRID-STOCKS. 



5 per cent of the total starch in 5 minutes; in about 2 

 per cent of the grains and 12 per cent of the total starch 

 in 15 minutes; in about 5 per cent of the grains and 

 20 per cent of the total starch in 30 minutes ; in about 

 5 per cent of the grains and 30 per cent of the total 

 starch in 45 minutes ; in about 6 per cent of the grains 

 and 31 per cent of the total starch in 60 minutes. 

 ( Chart D 438.) 



The reaction with cupric chloride begins in a few 

 grains in 30 seconds. Complete gelatinization occurs 

 in less than 0.5 per cent of the entire number of grains 

 and 3 per cent of the total starch in 5 minutes ; in about 

 1 per cent of the grains and 7 per cent of the total starch 

 in 15 minutes; in about 7 per cent of the entire number 

 of grains and 42 per cent of the total starch in 30 min- 

 utes; in about 13 per cent of the grains and 44 per cent 

 of the total starch in 45 minutes; in about 15 per cent 

 of the grains and 48 per cent of the total starch in 60 

 minutes. (Chart D 439.) 



The reaction with barium chloride begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains and 



1 per cent of the total starch in 5 minutes ; in about 0.5 

 per cent of the grains and 2 per cent of the total starch 

 in 15 minutes; slight advance in the grains and total 

 starch in 30 minutes ; in about 1 per cent of the grains 

 and 4 per cent of the total starch in 45 minutes ; in about 

 the same percentage of the grains and 5 per cent of the 

 total starch in 60 minutes. (Chart D 440.) 



The reaction with mercuric chloride begins in rare 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains 

 and total starch in 5 minutes; in less than 0.5 per cent 

 of the grains and 1 per cent of the total starch in 15 

 minutes ; in less than 0.5 per cent of the grains and 2 per 

 cent of the total starch in 30 minutes; in less than 0.5 

 per cent of the grains and 4 per cent of the total starch 

 in 45 minutes ; little if any further advance in 60 min- 

 utes. ( Chart D 441.) 



33. STARCHES OF IRIS PERSICA VAR. PURPTJREA, I. 



SINDJARENSIS, AND I. PDRSIND. 



IRIS PERSICA VAR.. PURPUREA (SEED PARENT). 



(Plate 19, fig. 112; Charts D 442 to D 462.) 



HISTOLOGIC PKOPERTIES. 



In form the grains are usually simple and isolated. 

 A few aggregates are noted and these are usually doublets 

 or triplets composed of rather small grains of equal size. 

 There is a moderate number of compound grains, usually 

 consisting of 2 components, but sometimes of 3 and, 

 rarely, of 8 or 9 components, and these are of three 

 types. In the first, which is the most common, there are 



2 or 3 components situated at or near the middle of the 

 grain, each consisting of a hilum and 2 or 3 distinct 

 lamella;, and completely surrounded by 1 to 4 common 

 secondary lamella, or joined only on opposite sides by 

 2 to 3 secondary lamella, and the whole surrounded by 

 1 or 2 secondary lamella?. The second type consists 

 of 2 to 8 or 9 components each represented only by a 

 hilum, and these are surrounded by a homogeneous- 

 looking mass outside of which are 1 to 4 or 5 lamella;. 

 The third type, which is of rare occurrence, consists of 2 

 components a common sized or large grain to the side 

 or distal end of which a small grain has become adherent, 



and the 2 are surrounded by 1 or 2 common secondary 

 lamellae. The grains are usually irregular in form and 

 the irregularities are due to the following causes in the 

 order of their frequency : ( 1 ) Protuberances of varying 

 sizes and shapes, usually from the sides but also not infre- 

 quently from the ends (on some of the grains these 

 protuberances may be so numerous as to give the grain a 

 warty appearance) ; (2) slight, shallow depressions and 

 elevations of the surface, giving an undulating or wavy 

 outline to the margin; (3) a small set of secondary 

 lamella; whose longitudinal axk is usually at a right angle 

 with that of the primary set; (4) very rarely, slight devi- 

 ation of the longitudinal axis of the grain with a conse- 

 quent bending of the grain near the distal end. The 

 conspicuous forms are ovoid, pure and somewhat broad- 

 ened, and nearly round. The additional forms are irregu- 

 larly quadrilateral with rounded angles, irregularly tri- 

 angular, dome-shaped, round, elongated elliptical with 

 or without a flattened distal end, and lenticular. The 

 grains are not flattened. 



The hilum, when not fissured, is a moderately dis- 

 tinct, round, refractive spot. It is usually fissured, how- 

 ever, and the fissures are extensive, irregular, and 

 branched, and have the following forms: (1) A single, 

 crooked, transverse, oblique or longitudinal line which 

 has many branches; (2) Y, T, or cruciform, all usually 

 with many branches and placed in various axes of the 

 grains; (3) a few irregularly stellate groups of fis- 

 sures; (4) 2 fissures forming a figure like a pair of 

 dividers. In the lenticular and elongated dome-shaped 

 grains the hilum is elongated lenticular in form, and the 

 whole hilum is occupied by a long, irregular, branching 

 fissure, juid in some of the compound grains there is a 

 long branching fissure passing through all the hila of the 

 components. The hilum is sometimes centric but com- 

 monly is eccentric from 0.44 to 0.27, usually 0.35, of the 

 longitudinal axis. 



The lamella are usually moderately distinct, some- 

 times very distinct, and sometimes not demonstrable. 

 They are rather coarse and are continuous, and near the 

 hilum they are round or lenticular in form, but near the 

 margin they are somewhat irregular and the irregulari- 

 ties are in general like those of the outline of the grain. 

 The number counted on the larger grains varies from 

 5 to 15, usually 8. 



In size the grains vary from the smaller which are 

 2 by 2(>,, to the larger elongated forms which are 50 by 

 30/t, and the larger broad forms which are 46 by 38/n, 

 in length and breadth. The common size is 32 by 



POLARISCOPIC PROPERTIES. 



The figure is distinct, but in the great majority of 

 the grains it is not well defined. The lines cross at a 

 right angle or at an acute angle which varies consider- 

 ably in size in the different grains. They are sometimes 

 subdivided into 2, 3, or 4 divisions near the margin 

 and are often somewhat bent. 



The degree of polarization varies from moderately 

 high to high (value 70). There is often some variation 

 in a given aspect of an individual grain. 



With selenite the quadrants are usually not clear-cut. 

 They are unequal in size and usually somewhat irregular 

 in shape. The colors are usually pure, but there are 

 some grains which have a greenish tinge. 



