MILTONIA. 



753 



The reaction with copper nitrate begins immediately. 

 Complete gelatinization occurs in about 52 per cent of the 

 grains and 84 per cent of the total starch in 5 minutes ; 

 in about 76 per cent of the grains and 95 per cent of the 

 total starch in 15 minutes; in about 83 per cent of the 

 grains and 96 per cent of the total starch in 30 minutes ; 

 in about 89 per cent of the grains and 97 per cent of the 

 total starch in 45 minutles; in about 93 per cent of the 

 grains and in over 99 per cent of the total starch in 60 

 minutes. (Chart D 612.) 



The reaction with cupric chloride begins immediately. 

 Complete gelatinization occurs in about 17 per cent of the 

 entire number of grains and 56 per cent of the total 

 starch in 5 jninutes; in about 30 per cent of the grains 

 and 70 per cent of the total starch in 15 minutes; in 

 about 36 per cent of the grains and 78 per cent of the 

 total starch in 30 minutes ; in about 45 per cent of the 

 grains and 81 per cent of the total starch in 45 minutes; 

 in about 57 per cent of the grains and 85 per cent of the 

 total starch in 60 minutes. (Chart D 613.) 



The reaction with barium chloride begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 1 per cent of the entire number of grains and 2 

 per cent of the total starch in 5 minutes ; in about 2 per 

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

 15 minutes; in alxrat 4 per cent of the grains and 7 per 

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

 cent of the grains and 10 per cent of the total starch in 

 45 minutes ; in about 40 per cent of the grains and 75 per 

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

 D 614.) 



The reaction with mercuric chloride begins imme- 

 diately. Complete gelatinization occurs in about 16 

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

 of the total starch in 5 minutes; in about 27 per cent 

 of the grains and 60 per cent of the total starch in 15 

 minutes ; in about 40 per cent of the grains and 75 per 

 cent of the total starch in 30 minutes; in about 49 per 

 cent of the grains and 80 per cent of the total starch in 

 45 minutes ; in about the same percentage of the grains 

 and 85 per cent of the total starch in 60 minutes. (Chart 

 D615.) 



MILTONIA RCEZLII (POLLEN PARENT). 



(Plate 24, fig. 140; Charts D 695 to D 615.) 



HISTOLOOIC PROPERTIES. 



In form most of the grains are simple and isolated, 

 with the exception of a moderately large proportion 

 (about as in M, vexillaria) which appear in aggregates of 

 usually from 2 to 6, occasionally 20, components in mosaic 

 arrangement. Compound grains are present, but are 

 somewhat less numerous than in M. vexillaria. Well- 

 defined pressure facets are present as in M. vexillaria. 

 The surface of the grains is generally irregular, and the 

 irregularities are more pronounced and appear in many 

 more grains than in M. vexillaria. The irregularities are 

 generally due to the same causes as in M. vexillaria, but 

 the shifting of the longitudinal axis is much more fre- 

 quent and sometimes so sharp as to result in an abrupt 

 bending of the grain ; the protuberances are often larger, 

 sometimes drawn out into a point at the proximal end, 

 and occur with more frequency; the outline is irregular 

 in many more grains, sometimes becoming undulating at 

 one end; a somewhat abrupt flaring may occur at the 



distal margin, this not being observed in M. vexillaria; 

 and secondary, tertiary, or irregularly placed groups 

 of lamellas are much more common and varied in arrange- 

 ment, which result in greater variation of the contour 

 of the sides of the grain. The conspicuous forms of 

 the isolated grains of the disaggregate type are ovoid, 

 sometimes squared at distal end ; pyriform ; low triangu- 

 lar with curved sides and rounded angles ; nearly round ; 

 ellipsoidal; and high triangular with curved sides and 

 rounded angles. The additional forms are broad lenticu- 

 lar, one side less curved than the other ; slender pyriform, 

 sometimes slightly curved to one side ; round, oyster-shell- 

 shaped; quadrangular with curved sides and rounded 

 angles; triangular with convex distal end (base) and con- 

 cave sides; potato-tuber-shaped; and grains of indefinite 

 form. The most conspicuous forms among the isolated 

 grains of the aggregate type are dome-shaped, either with 

 squared, pointed or diagonal, or slightly irregular distal 

 end (base) ; finger-shaped with either concave or slightly 

 irregular distal end; bell- jar-shaped with either squared 

 or concave distal end ; and grains of indefinite shape. The 

 conspicuous forms of the aggregates are doublets com- 

 posed of about equal components ; potato-tuber-shaped ; a 

 mosaic of varying number of components, doublets and 

 triplets consisting of 1 large and either 1 or 2 moderate- 

 sized components, the latter usually located at the proxi- 

 mal end; and rounded mosaics of varying numbers of 

 components. The aggregates are more varied with a 

 larger number of mosaic type than in M. vexillaria. The 

 grains are not usually flattened, although when a second- 

 ary set of lamella? is present some flattening is observed ; 

 this occurs more frequently than in M. vexillaria. 



The hilum is somewhat more frequently fissured 

 than in M. vexillaria, but when unfissured is less distinct 

 than in M. vexillaria. It can occasionally be made out 

 as either a small, lenticular or round spot, which varies 

 from non-refractive to quite refractive, as in M. vexil- 

 laria, the latter being even more rare than in that species. 

 The position varies from centric to quite eccentric. 

 Either a small, irregular or lenticular cavity, usually 

 directed longitudinally, is sometimes observed, somewhat 

 more frequently than in M. vexillaria. The cleft or clefts 

 at the hilum appear somewhat more frequently, but are 

 of about the same character as in M. vexillaria, the cluster 

 of irregularly placed clefts is, however, more commonly 

 present than in that species. The fissures which project 

 from the hilum are similar to those of M. vexillaria, 

 but are generally deeper, and the median fissure while 

 directed as in M. vexillaria is deeper, more frequently 

 branched, and much more commonly observed. The 

 eccentricity of the hilum varies from 0.46 to 0.11, com- 

 monly 0.33 to 0.2, of the longitudinal axis, less than 

 in the other parent. 



The lamellw are less often demonstrable, but when 

 observed they have the same general characteristics as in 

 M . vexillaria. The border with laterally extended distal 

 corners surrounding an ellipsoidal grain is much more 

 commonly observed. A definite secondary set of lamellae, 

 placed at a right angle with the primary set, is much more 

 frequently present than in M. vexillaria. The direction 

 of the lamella is more frequently changed than in M. 

 vexillaria, sometimes three or more groups may vary in 

 this respect as well as sometimes in width, refractivity, 

 etc. ; more groups occur, they vary more in character, and 



