498 



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



in about 0.5 per cent of the grains and 1 per cent of 

 the total starch in 30 minutes; in about the same per- 

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

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

 utes. ( Chart D 229.) 



The reaction with barium chloride begins in rare 

 grains in 2 minutes. 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 total starch in 15 minutes; little if 

 any further progress in 30, 45, and 60 minutes, respec- 

 tively. ( Chart D 230.) 



The reaction with mercuric chloride begins in rare 

 grains in two minutes. Complete gelatinization occurs 

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

 and total starch in 5 minutes; very slight progress in 

 15 and 30 minutes; in about 0.5 per cent of the grains 

 and 1 per cent of the total starch in 45 minutes; little 

 if any further advance in 60 minutes. (Chart D 231.) 



NEBINE SABNIENSIS TAR. COEUSCA MAJOB (POLLEN 

 PABENT). 



(Plates 7 and 8, figs. 38, 41, 43, and 46; Charts D 211 to D 231.) 



HISTOLOQIC PROPERTIES. 



In form the grains are usually simple and isolated, 

 and there is a much smaller number of both compound 

 grains and aggregates than in N. bowdeni. The com- 

 pound grains are of two types: One of 2 grains each, 

 each consisting of from 3 to 6 lamellae and both sur- 

 rounded by 3 to 5 or 6 common lamellae; the other of 

 1, 2, or 3 very small grains, each consisting of a hilum 

 and 1 or 2 lamellae, grouped (often at different levels) 

 at the proximal end of a large grain consisting of 

 14 to 20 common lamellae. The grains are much more 

 regular in form than those of N. bowdeni and any 

 irregularities which occur are due to the following 

 causes: (1) To a greater development of one part 

 of the distal margin or of one side than of the rest 

 of the grain; (2) to rounded protuberances, usually from 

 the proximal end or sides; (3) to a deviation of the 

 longitudinal axis with a consequent bending of the grain 

 in the center or near the distal end ; (4) in a few grains 

 a secondary set of lamellae whose longitudinal axis is at 

 an. angle with the longitudinal axis of the primary set; 

 (5) much less frequently than in N. bowdeni to notches 

 and depressions in the margin at various points. The 

 conspicuous forms are broad elliptical with or without a 

 flattened distal end, ovoid, and nearly round ; and among 

 the small grains, round and nearly round, and elliptical. 

 There are also clam-shell, pyriform, and irregularly 

 quadrilateral forms. The grains are not flattened, except 

 the broad forms which are not so much flattened as the 

 same forms in N. bowdeni. The grains are not so irregu- 

 lar nor so varied in form as those of N. bowdeni. 



The hilum is not so distinct as in N. bowdeni and is 

 even less frequently fissured than in that starch, but 

 when fissuring occurs the fissures have the following 

 forms: (1) A single, straight, transverse line, or an 

 irregularly stellate figure. The hilum is sometimes cen- 

 tric, but usually eccentric from 0.45 to 0.22, commonly 

 0.3, of the longitudinal axis. The hilum is more eccen- 

 tric than that of the grains of N. bowdeni. 



The lamellce are not quite so distinct as in N. bowdeni, 

 and as a rule there are not so many coarse lamellae as 

 in those grains. They are continuous near the hilum 

 but soon assume the form, often somewhat modified, of 

 the outline of the grain, and they are much more regular 

 in form than in N. bowdeni. The arrangement of the 

 lamellae varies somewhat from that of N. bowdeni, as 

 the fine lamellae are usually near the hilum and the coarse 

 lamellae at the distal end or in the central portion of 

 the grain ; the reverse, however, is the case in a moderate 

 number of grains. While in most grains one very coarse 

 refractive lamella is usually placed at about two-thirds 

 the distance from the hilum to the distal margin, some 

 grains which have otherwise no coarse lamellae have (in 

 addition to this especially refractive one) one or two 

 others which divide the fine lamellae into bands of varying 

 breadth. The number of lamellae counted on the larger 

 grains varies from 20 to 36, usually 28. 



The lamellae of these grains are not so distinct nor so 

 irregular as those of N. boivdeni, nor is there so large a 

 number of coarse lamellae as in those grains, and the 

 arrangement of fine and coarse lamella? varies in the kinds 

 of grains. 



In size the grains vary from the smaller which are 

 10 by 5/A and 7 by 7/j., to the larger broad forms which 

 are 46 by 40/A, rarely, 48 by 60/x, and the larger more elon- 

 gated forms which are 46 by 36/*, rarely 46 by 30/i, in 

 length and breadth. The common sizes are 32 by 30/i 

 and 32 by 20/t. The grains are not so large as those of 

 N.' bowdeni and there are not such broad forms as in 

 that starch. 



POLARISCOPIC PROPERTIES. 



The figure is nearly centric to eccentric, usually some- 

 what more eccentric, more distinct, and more clear-cut 

 than in N. bowdeni. The lines are rather coarse, not 

 so fine as in N. bowdeni, and less bent and bisected, and 

 usually intersect obliquely with less variation of the 

 angle than in N. bowdeni. There are fewer grains hav- 

 ing 5 and 6 arms to the figure than in N. bowdeni. 



The degree of polarization is moderate to very high 

 (value 90), higher than in N. bowdeni. It varies in dif- 

 ferent grains, a few having a moderate and the majority 

 a high polarization, but many more having a very high 

 polarization than in N. bowdeni. There is not so much 

 variation in polarization in the same aspect of a given 

 grain as in N. bowdeni. 



With selenite the quadrants are well defined and 

 almost invariably of unequal size, and there is less 

 irregularity in size and shape than in N. boivdeni. The 

 colors are more apt to be pure than in N. bowdeni, and a 

 greater number of grains have a greenish tinge. 



IODINE REACTIONS. 



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

 a moderately deep blue tinged with violet (value 60), the 

 color is deeper and less violet in tint than in N. bowdeni, 

 and it deepens as rapidly as in N. bowdeni, until it is deep 

 to very deep. With 0.125 per cent Lugol's solution, the 

 grains color a light to moderate blue with a tinge of 

 violet. The color is deeper than in N. bowdeni and less 

 violet in tint, and it deepens rapidly until it is deep. 

 After heating in water until the grains are gelatinized, 

 and then adding a 2 per cent Lugol's solution, the grains 

 color a moderate to very deep indigo-blue, deeper than in 



