78 EXPERIMENT STATION RECORD. 



the author in separating starches are described, and the results of investigations of 

 the microscopical character of the starch grains of a large number of plants are 

 reported, including the following: Sour sop, green mango, mango kernel, crab's eye 

 {Abrus precatorius), pigeon pea (Cajanus indicus), red pea, yam bean, cho-cho 

 (Sechium edule) nightshade, 3 varieties of Ipomeea, four o'clock, pink coralita 

 {Aniigonon insigne), cassava, breadfruit, 2 varieties of canna, arrowroot, ginger, 

 banana, plantain, yampie (Dioscorea trifida), 5 varieties of yam, tannia (Colocasia 

 esculenta) wild and cultivated, maize, and guinea corn. 



The large number of starches studied emphasizes the fact that the principal sources 

 of starch in the West Indies are the roots of the plants rather than in the seeds. All 

 the starches obtained from roots and tubers, the author states, showed a play of 

 colors with polarized light and may be readily grouped in 2 divisions. "In the 

 first are those bounded by rounded surfaces (i. e., either oval or ovate); hilum and 

 concentric rings clearly visible. The examples are the yams, the cannas, arrow- 

 root, and ginger. It will at once be noticed that these plants belong to natural 

 orders which are not far removed from one another, and emphasis is added to this 

 when it is observed that among the remaining starches in this group are to be found 

 those of the tribe Musea? (banana and plantain). 



" With regard to the remaining 'root' starches, they all agree in several charac- 

 ters. They all show some coloration with polarized light, and among the many- 

 angled there are some rounded forms, sugar-loaf forms being often present. There 

 is so much similarity among these starches that it will not be found an easy matter 

 to distinguish them until details as to appearance of hilum, measurements, etc., are 

 taken into account. The only starch in this group that is not a ' root ' starch is that 

 obtained from the green mango, just as the only 'seed ' starch in Class I was mango 

 starch. . . . The further study of fruit starches would, perhaps, be a profitable one. 

 So far as can be seen at present there is very little uniformity. ... As a general rule 

 it is stated that seed starches (at any rate, those of the cereals) show no iridescence 

 with polarized light; mango-seed starch, however, gives quite a brilliant play of 

 colors." 



In general the leguminous starches showed little or no iridescence when examined 

 with polarized light and considerable unifo runty was observed. "An exception has, 

 however, to be noted in the case of groundnut starch (Araclris hypogasa), as also in 

 the case of the starch from the root of the yam bean {Pachijrhizus tuberosum). In the 

 case of the latter we have what may be called the usual dicotyledonous 'root' form 

 of starch instead of the typical leguminous seed form. Evidently the striking uni- 

 formity in the case of leguminous starches is confined to the seeds. The only cereal 

 starches on this list will be found classed with the leguminous starches; the only 

 points of resemblance, however, are the invisibility of concentric rings, the absence 

 of iridescence with polarized light, and the presence of a more or less stellate hilum. 

 The starches of breadfruit and jack fruit are placed by themselves in the class which 

 contains wheat, barley, rye, etc." 



In his investigations the author has followed the classification of starches suggested 

 by Blyth, but believes that the systems for the classification of starches now in use 

 are unsatisfactory and should be revised. 



"Another interesting point is brought out by this investigation, which appears to 

 be worthy of mention here. "While in most cases there is a more or less distinct 

 resemblance between the starch grains of plants in any particular family, several 

 instances have been recorded where there is a decided variation. . . . [Among the 

 starches examined] there are some that might be utilized as producers of starch for 

 laundry purposes, while in other cases easily digested food, suitable for infants and 

 invalids, might be obtained, as for example, from the cho-cho root and the yam 

 bean." 



