732 



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



elongated grains, which are in the majority in this starch, 

 is very similar to that seen in the elongated grains of 71/. 

 arnoldiana, which are in the minority in that starch. 

 The differences noted are that the 2 furrows or fissures 

 from the hilum do not extend so close to the distal mar- 

 gin, but usually only half of the way between the hilum 

 and the margin. The starch comprehended between the 



2 fissures is fissured and separated into filaments as in 

 M. arnoldiana, but the rest of the distal starch is irregu- 

 larly fissured nearly to the margin. The proximal starch 

 and that at the sides forms a homogeneous-looking, re- 

 fractive band, except that immediately surrounding the 

 hilum, which is broken up by short regular cracks into 

 coarse granules. These granules, and those left as a 

 residue after the filaments of starch distal to the hilum 

 are gelatinized, are the most resistant part of the grain. 

 The distal starch gelatinizes first, then the homogeneous- 

 looking, marginal band at the proximal end and sides, 

 then granules at the distal end, and finally those at the 

 proximal end. In the second; method there are no 

 differences noted. The gelatinized grains are more swol- 

 len, have somewhat thicker capsules, and are more dis- 

 torted at the proximal end than in 71/. arnoldiana. 



The reaction with copper nitrate begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 2 per cent of the entire number of grains and 

 5 per cent of the total starch in 30 seconds; in about 5 

 per cent of the grains and 16 per cent of the total starch 

 in 1 minute; in about 45 per cent of the grains and 72 

 per cent of the total starch in 5 minutes; in about 68 

 per cent of the grains and 95 per cent of the total starch 

 in 15 minutes; in about 90 per cent of the grains and 

 98 per cent of the total starch in 30 minutes; very little 

 if any further advance in 45 and 60 minutes, respec- 

 tively. (Chart D 570.) 



The reaction with cupric chloride begins in a few 

 grains in 15 seconds. Complete gelatinization occurs in 

 1 per cent of the entire number of grains and 10 per cent 

 of the total starch in 1 minute ; in about 32 per cent of 

 the grains and 55 per cent of the total starch in 3 min- 

 utes; in about 35 per cent of the grains and 60 per cent 

 of the total starch in 5 minutes; in about 52 per cent of 

 the grains and 79 per cent of the total starch in 15 

 minutes; in about 61 per cent of the grains and 84 per 

 cent of the total starch in 30 minutes ; in about the same 

 percentage of the grains and 85 per cent of the total starch 

 in 45 minutes; in about 63 per cent of the grains and 

 89 per cent of the total starch in 60 minutes. (Chart 

 D571.) 



The reaction with barium chloride begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

 about 1 per cent of the entire number of grains and 5 

 per cent of the total starch in 5 minutes; in about 32 

 per cent of the grains and 51 per cent of the total starch 

 in 15 minutes; in about 35 per cent of the grains and 

 56 per cent of the total starch in 30 minutes; little if 

 any further advance occurs in 45 and 60 minutes, respec- 

 tively. (Chart D 572.) 



The reaction with mercuric chloride begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

 about 1 per cent of the entire number of grains and 10 

 per cent of the total starch in 1 minute ; in about 23 per 

 cent of the grains and 39 per cent of the total starch in 



3 minutes; in about 32 per cent of the grains and 54 



per cent of the total starch in 5 minutes; in about 42 

 per cent of the grains and 61 per cent of the total starch 

 in 15 minutes; in about 46 per cent of the grains and 

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

 50 per cent of the grains and 75 per cent of the total 

 starch in 45 minutes ; in about 55 per cent of the grains 

 and 79 per cent of the total starch in 60 minutes. (Chart 

 D573.) 



MUSA HYBRIDA (HYBRID). 



(Plate 23, fig. 135; Charts D 553 to D 573.) 



Histologic Properties. 



In form the grains are usually simple and isolated, 

 there being few compound grains and an occasional aggre- 

 gate. The compound grains belong to the two types 

 described under 71/. gilletii. The aggregates consist of 

 the types described under 21/. gilletii, and also of a type 

 composed of 12 or more small grains in the form of 

 an irregularly spherical mass. The grains are as moder- 

 ately regular in form as in 71/. gilletii, and any irregulari- 

 ties are due to the following causes, which are the same 

 as in M. gilletii: (1) A deviation of the longitudinal 

 axis of the grain near the center or near the distal end, 

 with a consequent curvature of the grain; (2) small 

 nipple-like or larger pointed projections from the proxi- 

 mal end; (3) a secondary set of lamella? whose longi- 

 tudinal axis is at an angle, usually a right angle, with 

 that of the primary set; (4) a greater development of 

 one part of the distal margin than of the rest of the 

 grain. The conspicuous forms are the elliptical, usually 

 slender with flattened distal end, but sometimes broad 

 with both ends rounded, and ovoid usually with a flat- 

 tened distal end. The additional forms are triangular 

 with curved base and rounded angles, round and nearly 

 round, pyriform, and quadrilateral with rounded angles. 

 Some of the grains of this specimen are crushed and 

 eroded, as in the parents. 



Most of the grains of the hybrid are, as in 71/. gilletii, 

 not flattened; but the broader forms are flattened, and 

 when viewed on edge have an irregularly rod-like form, 

 as in both parents. 



In form the grains of 71/. hyhrida show a much closer 

 relationship to 71/. gilletii than to 71/. arnoldiana, ex- 

 hibiting characteristics of each and both, and also certain 

 individualities. 



The hilum is as distinct as in both parents and is 

 more frequently fissured than in either parent, in this 

 characteristic resembling 71/. gilletii more than 71/. arnol- 

 diana. The fissures have the following forms which are 

 the same as in 71/. gilletii: (1) A single, straight or curved 

 line placed transversely or obliquely; (2) an irregularly 

 stellate arrangement of several fissures; (3) cruciate-, 

 T- or Y-shaped; (4) flying-bird shape. The hilum is 

 eccentric from 0.42 to 0.2, usually 0.23, of the longitu- 

 dinal axis, about the same as in the parents. In the 

 character and eccentricity of the hilum 71/. hybrida shows 

 a closer relationship to 71/. gilletii than to 71/. arnoldiana. 



The lamella; are, as in M. gilletii, rather fine, distinct 

 rings which are continuous near the hilum but discon- 

 tinuous at or near the distal end. In character and 

 arrangement they are essentially the same as in M. 

 gilletii. The number counted on the larger grains varies 

 from 12 to 34, usually 28, nearly the same as in 71/. 

 arnoldiana and more than in 71/. gilletii. 



