772 



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



ment with the reagent. Lamellae also become more dis- 

 tinct in some grains. Gelatinization begins in the in- 

 terior of the grain, in man}' at the hilum or some point 

 corresponding to it, and delicate branching fissures pro- 

 ceed from this point fauwise to the margin and divide 

 the material of the grain into two granules, and as these 

 slowly gelatinize the grain swells slowly and becomes 

 more nearly transparent until they are finally completely 

 gelatinized. In the majority of the grains, however, 

 translucent lines appear running criss-cross in all direc- 

 tions through the grain, dividing the whole interior into 

 granules of various sizes and then into fragments which 

 gradually separate from one another, all the while be- 

 coming more translucent, until they are gelatinized with 

 much folding of the capsules of the grains. The gela- 

 tinized grains are moderately large and very much dis- 

 torted. Sometimes the capsule is dissolved and then the 

 contents of the capsule before gelatinization is complete. 



The reaction with sodium salicylate begins imme- 

 diately. Complete gelatinization occurs in about 68 per 

 cent of the entire number of grains and 76 per cent of 

 the total starch in 3 minutes; in about 84 per cent of 

 the grains and 93 per cent of the total starch in 5 min- 

 utes; in about 96 per cent of the grains and 98 per cent 

 of the total starch in 10 minutes. (Chart D 626.) 



The hilum and the lamella? are not visible in most of 

 the grains. A very narrow and not very refractive 

 band is formed about the margin of the grain before 

 gelatinization begins. Gelatinizatiou begins at various 

 points around the margin, usually at small projections 

 from the margin, and progresses from these points around 

 the margin, until all the marginal starch is somewhat 

 irregularly gelatinized. It then progresses inward, the 

 ungelatinized part of the grain assuming first a pitted 

 and then a finely granular appearance and then becoming 

 gelatinized. The central part of the grain is the most 

 resistant, and this is usually split into several pieces which 

 are gelatinized separately, but occasionally small gran- 

 ules only are broken off until all is gelatinized. The 

 gelatinized grains are large and very much distorted and 

 show very little resemblance to the form of the untreated 

 grain. 



CALANTHE VESTITA VAE. RUBRO-OCULATA (POLLEN 

 PARENT). 



(Charts D 019 to D 626.) 



HISTOLOQIC PROPERTIES ( See Foot-note, page "GO ) . 

 In form most of the grains are simple and isolated, 

 with the exception of a few which appear as aggregates 

 usually of 2 components. Compound and semi-compound 

 grains of 2 components are occasionally observed. Well- 

 defined pressure facets are occasionally observed. The 

 surface of the grain is frequently regular, but slight irreg- 

 ularity may be observed, which is chiefly due to the fol- 

 lowing causes : A shifting of the longitudinal axis which 

 is occasionally quite abrupt ; a difference in the contour of 

 the sides in an otherwise regular grain ; occasional sinuous 

 outline, and to a rounded or blunt lateral swelling. The 

 conspicuous forms are ovoid, ellipsoidal, pyriform, al- 

 most round, and rounded triangular. In addition there 

 are ovoid with squared or broadened and concave distal 

 end, reniform, irregular rhomboidal, and pyriform ab- 

 ruptly curved at narrow end. The clearly defined 

 separated grains are usually dome-shaped, but as the 



components of aggregates frequently are placed laterally 

 and are either somewhat pyriform or ovoid in shape; 

 grains with one side more flattened may be separated 

 grains. The grains vary from slightly to moderately 

 flattened, with mpre of the former when seen on edge; 

 they are either ovoid or narrow ellipsoidal. 



The hilum is either a round or lenticular spot which 

 is usually non-refractive; when lenticular it may be 

 located either transversely or diagonally. Either a small 

 rounded or lenticular cavity is sometimes present. The 

 hilum is more frequently fissured, usually by 1 transverse 

 straight, crescentic or irregularly bent cleft, or a group 

 of irregularly placed clefts; and clefts so arranged as 

 to form a soaring-bird figure. Longitudinal fissures 

 frequently leave the hilum, such as 1 straight or diagonal, 

 which may be either clean-cut or branched and 2 which 

 are directed obliquely towards the distal corners. The 

 fissures both at and proceeding from the hilum are 

 usually deep and refractive. The position varies from 

 centric to quite eccentric ; the range of eccentricity varies 

 from 0.42 to 0.12, commonly about 0.33 of the longitu- 

 dinal axis. 



The lamellce are not usually demonstrable, but occa- 

 sionally 1 or 2 are distinct and moderately coarse. When 

 2 are present, 1 forms a circular ring directly around 

 the hilum, and the other one a short distance from it. 

 If but 1 lamella is distinct it is generally located moder- 

 ately near the margin, at which region a band then ap- 

 pears, even more refractive than the main body of the 

 grain. A few lamellae are occasionally demonstrable in 

 the main body of the grain, being bounded by a refractive 

 marginal border. Lamella? in the blunt protuberances 

 at one side of the grain were not demonstrable, although 

 this probably represents a secondary growth. Earely 16 

 can be counted on medium-sized grains, 29 on large pyri- 

 form grains. These larger grains are scattered among the 

 more common medium-sized grains. 



The size of the grains varies from the smaller, which 

 are 5 by 4/u,, to the larger, which are 40 by 28/A in length 

 and breadth. The common size is about 22 by 18/x in 

 length and breadth. 



POLARISCOPIC PROPERTIES. 



The figure varies from centric to quite eccentric, 

 more of the eccentric, and is more frequently clean-cut. 

 The lines in most grains are moderately fine, often 

 broadening towards the margin and usually intersecting 

 either at right angles or obliquely, though occasionally 

 arranged in a median line with bisected ends. The lines 

 are more frequently straight, although they are moder- 

 ately often bent and bisected. In a few grains the lines 

 are broad, or rarely an arrangement is found which re- 

 sembles a rectangular box open at the corners, infre- 

 quently pierced at one or more points on the sides. 

 Double and multiple figures are observed. 



The degree of polarization is moderate to very high, 

 commonly high (value 70), much higher than in C. rosea. 

 There is also considerable variation in the same aspect 

 of a grain, a small proportion of them, either the central 

 part or the lower median quadrant, being exceedingly low. 



With selenite the quadrants of the majority are 

 sharply defined, unequal in size, and slightly to quite 

 irregular in shape. The colors are usually pure, the 



