718 



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



The reaction with pyrogallic acid begins imme- 

 diately. Complete gelatinization occurs in 0.5 per cent 

 of the entire number of grains and 43 per cent of the 

 total starch in 5 minutes; in about 43 per cent of the 

 grains and 87 per cent of the total starch in 15 minutes ; 

 in about GO per cent of the grains and 92 per cent of the 

 total starch in 30 minutes; in about the same percentage 

 of the grains and 96 per cent of the total starch in 45 

 minutes; in about 63 per cent of the grains and 97 per 

 cent of the total starch in 60 minutes. (Chart D 541.) 



The hilum and lamella? are as distinct as in B. soco- 

 irana. Gelatinization begins at the hilum and progresses 

 as in B. double deep rose, except that the starch compre- 

 hended between the 2 fissures which proceed from either 

 side of the hilum is usually not so distinctly fissured and 

 that there are a few grains in which this part of the 

 grain is divided by a double row of slanting fissures as in 

 B. socotrana. The gelatinized grains are more swollen, do 

 not have such thick capsules, and are somewhat more dis- 

 torted than in B. double deep rose. In this reaction B. suc- 

 cess shows qualitatively a closer relationship to B. double 

 deep rose than to B. socotrana. (See note, page 698.) 



The reaction with nitric acid begins immediately. 

 Complete gelatinization occurs in 100 per cent of the 

 entire number of grains and total starch in 15 seconds. 

 (Chart D 543.) 



The hilum becomes distinct in all the grains, attended 

 by the formation of a bubble in more grains than in B. 

 double deep rose. The lamella? are as distinct as in 

 B. socotrana. Gelatinization begins at the hilum and 



progresses as in B. double deep rose, except that the 

 starch comprehended between the 2 fissures which pro- 

 ceed from the hilum is in some grains divided by a double 

 row of slanting fissures as in B. socotrana, and in all 

 the grains becomes more distinctly granular than in B. 

 double deep rose. The gelatinized grains are as much 

 swollen, have as thin capsules, and are somewhat more 

 distorted than in B. double deep rose. In this reaction 

 B. success shows qualitatively a somewhat closer rela- 

 tionship to B. double deep rose than to B. socotrana. 



The reaction with strontium nitrate begins imme- 

 diately. Complete gelatinization occurs in about 75 per 

 cent of the entire number of grains and 88 per cent of the 

 total starch in 1 minute; in about 98 per cent of the 

 grains and 99 per cent of the total starch in 2 minutes. 

 (Chart D544.) 



The hilum and the lamellae are as distinct as in B. 

 socotrana. Gelatinization begins at the hilum and pro- 

 gresses as in B. double deep rose, except that the 2 fis- 

 sures which proceed from either side of the hilum are 

 more distinct and longer and that the distal starch 

 is rarely invaded by longitudinal fissures from the mar- 

 gin. A few of the grains show a double row of slanting 

 fissures distal to the hilum, and the part bounded by the 

 fissures is gelatinized as in B. socotrana. The gela- 

 tinized grains are as much swollen and have as thick 

 capsules as in B. double deep rose, but are somewhat more 

 distorted than in that starch. In this reaction B. success 

 shows qualitatively a somewhat closer relationship to 

 B. double deep rose than to B. socotrana. 



12. RICHARDIA. 



The basis of this genus consists of a few well-marked 

 species that are native of South America. Some of the 

 species and the varieties are in common cultivation and 

 popularly known as callas, which, however, like the 

 Arum callas do not belong to the true monotypic genus 

 Calla. 



Starches of the following parent-stocks and hybrid- 

 stocks were studied : 



40. R. albo-maculata Hook, (seed parent), R. elliottiana Knight 

 (Calla elliottiana Hort. ) (pollen parent), and R. mrs. 

 roosevelt (hybrid). 



The specimens were'obtained from the growers, B. H. 

 Krelage and Son, Haarlem, Holland. 



40. Starches of Richardia albo-maculata, R. 

 elliottiana, and r. mrs. roosevelt. 



Richardia albo-maculata (Seed Parent). 



(Charts D 545 to D 565.) 

 Histologic Pboperties. 

 In form the grains are simple and usually occur as 

 separated components of aggregates with the exception of 

 a few which appear in disintegrating aggregates, as rare 

 complete doublets of 2 small or 1 large and 1 small com- 

 ponent, and as permanently isolated grains. Pressure 

 facets are present on most of the grains, and the grains 

 are usually regular, with the exception that the sides and 

 angles of a given polygonal grain may occasionally show 

 a variation, and that depressions, probably due to pres- 

 sure, may occur at indefinite points upon the surface of 

 rounded and ellipsoidal grains. The conspicuous forms 



of the separated component grains are polygonal, low 

 dome-shaped with squared or pointed distal end, high 

 dome-shaped with a plane or concave distal end, and 

 rounded with concave distal end. The conspicuous forms 

 of the permanently isolated grains are round, nearly 

 round, and ellipsoidal. The grains are not flattened, 

 excepting at the pressure facets. 



The hilum is usually indistinct and seldom unfissured. 

 It is occasionally observed as a round, non-refractive spot. 

 A small, rounded cavity is rarely present. The hilum is 

 centric in the majority of grains, but may have a range 

 of eccentricity from 0.45 to 0.35, rarely 0.25, of the 

 longitudinal axis. 



The lamella? are not usually demonstrable, but can 

 occasionally be observed as moderately fine rings which 

 are circular near the hilum and elsewhere have the form 

 of the outline of the grain. The number throughout the 

 entire grain can rarely be counted, but there may be 

 8 on some of the larger, dome-shaped doublets. 



The size of the grains varies from the smaller which 

 are 3 by 2/x, to the larger permanently isolated grains 

 which are 16 by 16/a, and the larger separated components 

 which are 16 by 24/a, in length and breadth. The com- 

 mon size of the separated components is about 8 by 7/a, of 

 the originally isolated grains 12 by 12/t, in length and 

 breadth. 



Polaeiscopic Properties. 



The figure is usually centric to slightly eccentric, 

 rarely quite eccentric, with more of the centric. The 

 figure is usually distinct, although occasionally the lines 

 are not clear throughout entire figure. The lines are 



