PHAIUS MILTONIA . 



749 



about 3 per cent of the entire number of grains and 10 

 per cent of the total starch in 5 minutes ; in about 20 per 

 cent of the grains and 62 per cent of the total starch 

 in 15 minutes ; in about 33 per cent of the grains and 76 

 per cent of the total starch in 30 minutes; in about 51 

 per cent of the grains and 82 per cent of the total starch 

 in 45 minutes ; in about 52 per cent of the grains and 86 

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

 D590.) 



The reaction with copper nitrate begins immediately. 

 Complete gelatinization occurs in about 80 per cent of 

 the entire number of grains and 98 per cent of the total 

 starch in 5 minutes ; in about 95 per cent of the grains 

 and over 99 per cent of the total starch in 10 minutes; 

 in about 97 per cent of the grains and over 99 per cent 

 of the total starch in 15 minutes. (Chart D 591.) 



The reaction with cupric chloride begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 18 per cent of the grains and 65 per cent of the 

 total starch in 5 minutes; in about 50 per cent of the 

 grains and 82 per cent of the total starch in 15 minutes; 

 in about 67 per cent of the grains and 92 per cent of the 

 total starch in 30 minutes; in about 80 per cent of the 



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

 in about 82 per cent of the grains and 96 per cent of the 

 total starch in 60 minutes. (Chart D 592.) 



The reaction with barium chloride begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

 about 0.5 per cent of the entire number of grains and 

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

 1 per cent of the grains and 3 per cent of the total starch 

 in 15 minutes; a slight advance in the grains and 5 per 

 cent of the total starch in 30 minutes; in about 2 per 

 cent of the grains and 6 per cent of the total starch in 45 

 minutes ; in about 3 per cent of the grains and 8 per cent 

 of the total starch in 60 minutes. (Chart D 593.) 



The reaction with mercuric chloride begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 18 per cent of the entire number of grains and 68 

 per cent of the total starch in 5 minutes ; in about 45 per 

 cent of the grains and 85 per cent of the total starch in 15 

 minutes; in about 61 per cent of the grains and 90 per 

 cent of the total starch in 30 minutes; in about 63 per 

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

 45 minutes ; little if any further advance in 60 minutes. 

 (Chart D 594.) 



15. MILTONIA. 



This genus of orchids includes a dozen or more well- 

 known species, and there are as many hybrids and also 

 many varieties. Starches from the pseudobulbs of the 

 following parent-stocks and hybrid-stocks were studied : 



43. M. vcxillaria Nichols (Odontoglossum vexillarium Reichb. 

 f.) (seed parent), Af. rcezlii Nichols (Odontoglossum 

 rcezlii Reiclib. f. ) (pollen parent), and M. bleuana 

 (hybrid). The parent-stocks are closely allied, differing 

 only in minor respects. 



The specimens were obtained from Sander and Sons, 

 St. Albans, England. 



43. STARCHES OF MILTONIA VEXILLAEIA, M. KCEZLII, 

 AND M. BLEUANA. 



MILTONIA VEXILLARIA (SEED PARENT). 



(Plate 24, fig. 139; Charts D 595 to D 615.) 

 HISTOLOOIC PBOPEHTIES. 



In form the grains are mostly simple, and also iso- 

 lated with the exception of a moderately large proportion 

 which appear in aggregates of usually 2 to 4, rarely 12, 

 components, forming a rounded mosaic. Compound 

 grains are occasionally present, and usually consist of 

 from 2 to 3 components. Well-defined pressure facets are 

 found on many grains. The outline of the grains is fre- 

 quently irregular, which is chiefly due to the following 

 causes : Shifting of the longitudinal axis ; inequalities in 

 the surface varying from slight to concave indentations ; 

 variation in the contour of the sides, especially noted in 

 dome-shaped grains in which one side is much more slant- 

 ing than the other ; irregularity of the pressure facet of 

 dome-shaped grains ; a small protuberance which may be 

 located at varying points on the surface ; and to a rounded 

 unilateral swelling which appears to be composed of a 

 secondary set of lamella?. The most conspicuous forms 

 of the isolated grains of the disaggregate-type are ovoid, 

 sometimes with squared distal end, round, ellipsoidal, 

 pyriform, and almost round. The additional forms of 



this type are oyster-shell-shaped; elongated, narrow 

 ovoid; low triangular which may have either rounded or 

 concave distal corners; and grains of indefinite shape. 

 The conspicuous forms among the isolated grains of the 

 aggregate type are dome-shaped with either squared, 

 pointed, diagonal or slightly irregular distal end; bell- 

 jar-shaped with either squared or concave distal end; 

 ovoid with concave distal end; and quadrangular with 

 curved sides. The most conspicuous forms of the aggre- 

 gates are doublets with components of about equal size ; 

 1 large component, either ovoid or pyriform, with 1 

 moderate-sized component at 1 of the distal corners; 3 

 moderate-sized components in linear arrangement, the 

 middle being the largest ; 1 large component with 1 mod- 

 erate-sized component ait the distal corners; and 4 com- 

 ponents in compact arrangement. The grains are not 

 usually flattened. 



The hilum is often fissured, but sometimes it may be 

 observed as either a small, lenticular or round, non- 

 refractive to quite refractive spot, this spot probably 

 representing a cavity. Either a small rounded or irregu- 

 lar cavity is occasionally present. It varies in position 

 from centric to quite eccentric. The clefts at the hilum 

 are quite varied in structure, chiefly among which are 

 the following : 1 short, transverse, often somewhat bent ; 

 1 short diagonal; a cluster of irregularly arranged fis- 

 sures ; and thorn-shape. Fissures often project from the 

 hilum or the clefts thereat, and with the latter may form a 

 cruciate, a soaring-bird, or a Y-shaped figure, the latter 

 either upright or inverted ; either 2 short fissures some- 

 times pass from either side of the hilum and are directed 

 obliquely toward the distal corners, or 1 branched longi- 

 tudinal fissure may pass from the center of the hilum 

 and not infrequently be slightly diagonal, probably due 

 to shifting of the longitudinal axis. In the dome-shaped 

 grains 2 fissures pass from either side of the hilum and 

 are directed obliquely toward the distal corners, 1 fre- 

 quently being much longer and deeper than the other, 



