688 



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



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

 total starch in 5 minutes; in about 6 per cent of the 

 grains and 9 per cent of the total starch in 15 minutes ; in 

 about 9 per cent of the grains and 13 per cent of the 

 total starch in 30 minutes ; in about the same percentage 

 of the grains and 16 per cent of the total starch in 45 

 minutes ; in about the same percentage of the grains and 

 total starch in 60 minutes. (Chart D 498.) 



The reaction with strontium nitrate begins^ imme- 

 diately. Complete gelatinization occurs in about 8 per 

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

 the total starch in 5 minutes; in about 18 per cent of the 

 grains and 24 per cent of the total starch in 15 minutes; 

 in about 26 per cent of the grains and 38 per cent of the 

 total starch in 30 minutes; in about 29 per cent of the 

 grains and 41 per cent of the total starch in 45 minutes ; 

 in about 38 per cent of the grains and 50 per cent of the 

 total starch in 60 minutes. (Chart D 499.) 



The reaction with cobalt nitrate begins immediately. 

 Complete gelatinization occurs in about 3 per cent of the 

 grains and 7 per cent of the total starch in 5 minutes ; 

 in about 5 per cent of the grains and 11 per cent of the 

 total starch in 15 minutes; in about 7 per cent of the 

 grains and 15 per cent of the total starch in 30 minutes; 

 in about the same percentage of both the grains and 

 total starch in 45 and 60 minutes, respectively. ( Chart 

 D 500.) 



The reaction with copper nitrate begins immediately. 

 Complete gelatinization occurs in about 5 per cent of 

 the grains and 11 per cent of the total starch in 5 min- 

 utes ; in about 6 per cent of the grains and 20 per cent 

 of the total starch in 15 minutes; in about the same 

 percentage of the grains and slight advance in the total 

 starch (about 24 per cent) in 30 minutes; in about 10 

 per cent of the grains and 28 per cent of the total starch 

 in 45 minutes; in about 13 per cent of the grains and 

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

 D501.) 



The reaction with cupric chloride begins imme- 

 diately. Complete gelatinization occurs in about 7 per 

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

 total starch in 5 minutes; in about 9 per cent of the 

 grains and 14 per cent of the total starch in 15 minutes; 

 in about 10 per cent of the grains and 16 per cent of the 

 total starch in 30 minutes ; in about the same percentage 

 of both the grains and total starch in 60 minutes. (Chart 

 D 502.) 



The reaction with barium chloride begins in a very 

 few grains immediately. Complete gelatinization occurs 

 in about 0.5 per cent of the entire number of grains and 

 2 per cent of the total starch in 5 minutes ; very slight 

 advance in 15 minutes ; in about 1 per cent of the grains 

 and 3 per cent of the total starch in 30 minutes ; very 

 slight if any advance occurs in 45 and 60 minutes, 

 respectively. (Chart D 503.) 



The reaction with mercuric chloride begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 3 per cent of the entire number of grains and 6 

 per cent of the total starch in 5 minutes; in about 6 

 per cent of the grains and 9 per cent of the total 

 starch in 15 minutes; in about the same percentage 

 of the grains and 12 per cent of the total starch in 30 

 minutes ; in about the same percentage of the grains and 



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

 the same percentage of the grains and 15 per cent of the 

 total starch in 60 minutes. (Chart D 504.) 



Tritonia crocosmia aurea (Pollen Parent). 



(Plate 20, fig. 119; Charts D 484 to D 504.) 

 Histologic Properties. 

 In form the majority of the grains are simple and are 

 the separated components of aggregates, with the excep- 

 tion of a few which either remain in small aggregates 

 or those which are permanently isolated grains; the 

 proportion of the last named is considerably larger than 

 in T. pottsii. Compound grains of 2 components are 

 occasionally observed; they are more numerous than in 

 T. pottsii. Well-defined pressure facets are present in the 

 majority of grains, but not so numerous as in T. pottsii. 

 The surface of the grains is usually regular, which is 

 found in a few more grains than in T. pottsii, although 

 the same irregularities may occur ; and in addition reticu- 

 lar markings are occasionally found on the large grains, 

 which probably are the result of pressure of small grains. 

 While such markings were not noted in T. pottsii, yet 

 they may be obscured by the foreign material that often 

 incrusts the larger grains of the specimen studied. The 

 conspicuous forms of the separated component grain's 

 are the same as in T. pottsii, but the ovoid form with 

 squared or pointed end, the nearly round with concave 

 depression, and the high bell-jar shaped, are more numer- 

 ous than in T. pottsii. The conspicuous form of the 

 permanently isolated grains are the same as in T. pottsii, 

 but more of the ovoid and the triangular forms are found, 

 the latter being more elongated than in T. pottsii. The 

 aggregates usually consist of from 2 to 4 components 

 which may be of about equal size and compactly arranged, 

 as is generally found in T. pottsii; but more frequently 

 they consist of 1 small component adhering to the surface 

 of 1 large component ; the latter are much more numerous 

 than in T. pottsii. The grains, as in T. pottsii, are not 

 flattened. 



The hilum is a small, round or lenticular spot, which 

 is more refractive than in T. pottsii. It is usually single, 

 but rarely double, as in T. pottsii. A small, rounded or 

 irregular cavity is found more frequently at the hilum 

 than in T. pottsii. The hilum is frequently fissured, 

 much more often than in T. pottsii, and the clefts are, as 

 a rule, deeper. The structure of the clefts is the same 

 as that noted for T. pottsii, with the addition of dragon- 

 fly, cruciate, and T-shaped figures. Fissures extending 

 distalward from the hilum are observed, the same as 

 found in T. pottsii, with addition of an occasional single, 

 longitudinal fissure found in ovoid grains. The hilum is 

 either centric or is eccentric from 0.45 to 0.25, commonly 

 0.35, of the longitudinal axis. 



The lamella; are usually not distinct, and are demon- 

 strable throughout the grain in somewhat fewer grains 

 than in T. pottsii. Most of them are fine to moderately 

 fine ; when demonstrable, often one is located at varying 

 distances from the hilum, and is more distinct, coarser, 

 and slightly refractive, this being observed in a larger 

 proportion of grains than in T. pottsii. The lamellae 

 around the hilum may form circular rings, but a short 

 distance outward tend to follow the outline of the grain, 

 as in T. pottsii. A marginal band in which the lamellae 

 are refractive and usually very indistinct is observed 



