BEGONIA. 



699 



per cent of the total starch in 2 minutes ; in more than 

 99 per cent of the grains and total starch in 3 minutes. 

 (Chart D520.) 



The reaction with strontium nitrate begins imme- 

 diately. Complete gelatinization occurs in about 89 per 

 cent of the entire number of grains and 96 per cent of 

 the total starch in 1 minute; in 100 per cent of the grains 

 and total starch in 2 minutes. (Chart D 521.) 



The hilum becomes distinct, unattended by the for- 

 mation of a bubble in any of the grains. The lamellae 

 are never distinct and are usually not visible. Gela- 

 tinization begins at the hilum which swells rapidly, more 

 toward the proximal than toward the distal end. Two fis- 

 sures are rarely seen to extend from either side of the 

 hilum toward the distal margin. Usually the hilum 

 simply enlarges rapidly, and the more resistant starch 

 of the grain forms a thick, refractive, homogeneous- 

 looking marginal band which is much thicker and 

 broader at the distal than at the proximal end and sides. 

 This marginal band grows thinner, and more nearly 

 transparent, and is finally gelatinized, first at the proxi- 

 mal and last at the distal end. In the grains in which 

 2 fissures extend from either side of the hilum, there 

 is no other difference to be noted in the methods of 

 gelatinization. The gelatinized grains are much swollen, 

 have rather thick capsules, and are somewhat distorted. 



Comparison of the strontium-nitrate reactions be- 

 tween B. socotrana and B. single crimson scarlet shows : 



The hilum and lamellae are more distinct than in B. 

 single crimson scarlet. Gelatinization begins at the hilum 

 and progresses rather differently from B. single crimson 

 scarlet. The hilum swells somewhat, and 2 distinct 

 fissures proceed from either side nearly to the distal 

 margin, the starch comprehended between them is fis- 

 sured by fine longitudinal fissures, and then in many 

 grains by a double row of slanting fissures which appear 

 first near the hilum and then progressively toward the 

 distal end as the starch near the hilum is gelatinized and 

 the grain swells. As the starch thus fissured is gela- 

 tinized it leaves a residue of small refractive protuber- 

 ances projecting into the interior of the swelling grains. 

 The starch at the proximal end and sides forms at the 

 margin a homogeneous-looking refractive band which is 

 moderately rapidly gelatinized. The gelatinized grains 

 are more swollen, do not have such thick capsules, and 

 are more distorted than in B. single crimson scarlet. 



The reaction with cobalt nitrate begins immediately. 

 Complete gelatinization occurs in about 36 per cent of 

 the entire number of grains and 70 per cent of the total 

 starch in 5 minutes; in about 56 per cent of the grains 

 and 88 per cent of the total starch in 15 minutes; in 

 about 65 per cent of the grains and 93 per cent of the 

 total starch in 30 minutes; in about 68 per cent of the 

 grains and 95 per cent of the total starch in 45 minutes; 

 in about 71 per cent of the grains and 96 per cent of the 

 total starch in 60 minutes. (Chart D 522.) 



The reaction with copper nitrate begins immediately. 

 Complete gelatinization occurs in about 90 per cent of 

 the entire number of grains and 99 per cent of the total 

 starch in 2 minutes; in 100 per cent of the grains and 

 total starch in 5 minutes. (Chart D 523.) 



The reaction with cupric chloride begins immediately. 

 Complete gelatinization occurs in about 75 per cent of 

 the entire number of grains and in more than 99 per cent 



of the total starch in 3 minutes; in about 87 per cent of 

 the grains and in more than 99 per cent of the total starch 

 in 5 minutes. (Chart D 524.) The grains are very 

 quickly gelatinized with the exception of a small area at 

 the distal margin. 



The reaction with barium chloride begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

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

 5 per cent of the total starch in 5 minutes; in about 7 

 per cent of the grains and 23 per cent of the total starch 

 in 15 minutes; in about 32 per cent of the grains and 

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

 39 per cent of the grains and 66 per cent of the total 

 starch in 45 minutes; little if any further advance in 

 60 minutes. (Chart D 525.) 



The reaction with mercuric chloride begins imme- 

 diately. Complete gelatinization occurs in about 35 per 

 cent of the entire number of grains and 80 per cent of 

 the total starch in 5 minutes ; in about 74 per cent of the 

 grains and 96 per cent of the total starch in 15 minutes; 

 in about 80 per cent of the grains and 98 per cent of the 

 total starch in 30 minutes; in about 82 per cent of the 

 grains and 99 per cent of the total starch in 45 minutes; 

 in about 86 per cent of the grains and in more than 99 

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

 D526.) 



BEGONIA MRS. HEAL (HYBRID). 



(Plate 21, fig. 123; Charts D 505 to D 626.) 

 HISTOLOGIC PROPERTIES. 



In form the grains are almost solely simple and iso- 

 lated, a compound grain or an aggregate may be seen of 

 the same types as described under B. single crimson scar- 

 let. The grains are usually regular somewhat more 

 often irregular than in B. socotrana, and somewhat less 

 often than in B. single crimson scarlet. The irregulari- 

 ties are due to the same causes as described under B. soco- 

 trana with the addition of a deviation of the axis in 

 two different directions with a consequent bending of 

 the grain at both ends. This is not seen in either parent. 

 The conspicuous forms are elongated elliptical and ovoid. 

 The additional forms are round and nearly round, irregu- 

 larly triangular, quadrilateral with rounded corners, rod- 

 shaped, and, rarely, oyster-shell-shaped. The few broad 

 forms are somewhat flattened, as in both parents, and 

 when seen on edge have an elongated elliptical or ovoid 

 shape. In form B. mrs. heal shows a closer relationship 

 to B. socotrana than to B. single crimson scarlet. 



The hilum, as in B. single crimson scarlet, is a rather 

 indistinct, small, round spot which is rarely fissured. 

 When fissuring occurs the forms are the same as in B. 

 single crimson scarlet. The hilum is eccentric from 0.3 

 to 0.17, usually 0.18, of the longitudinal axis, which is the 

 same as in B. socotrana and 0.07 more eccentric than in 

 B. single crimson scarlet. In the character of the hilum 

 B. mrs. heal shows a closer relationship to B. single 

 crimson scarlet, and in the eccentricity to B. socotrana. 



The Iamello3 are more distinct and are not so fine as 

 in the parents, resembling B. socotrana more closely. 

 Otherwise the characteristics and the arrangement of the 

 lamellae are the same as in B. socotrana, except that when 

 the grain is composed of both primary and secondary 

 parts the primary grain is surrounded by a single, broad, 

 refractive lamella, as in B. single crimson scarlet. The 



