344 BOTANICAL GAZETTE [November 



*'Spharokrystalloide." Meyer (21) has enlarged upon this view 

 and considers the starch grain to be made up of two kinds of 

 acicular crystals, which he calls ** Trichiten," these being com- 

 posed of a-amylose and )8-amylose, there being also present in 

 the grains that are colored red with iodine, amylodextrin and 

 dextrin. He further says that most starch grains consist alto- 

 gether or nearly so of amylose, and that these are colored blue 

 with iodine. These latter starch grains are made up of sphere- 

 crystals of amylose, arranged in layers, and these layers may 

 consist of crystals of either a-amylose or /3-amylose, or both, 

 some starch grains containing in addition, as already stated, 

 large amounts of amylodextrin and dextrin. 



Starch grains are distinguished from one another by the follow- 

 ing particulars : (i) The origin in the plant; (2) the shape of 

 the grain; (3) the size of the grain ; (4) the position of the point 

 of origin of growth ;= (5) the shape of the point of origin of 

 growth; (6) distinctness of lamellae; (7) the direction of the 

 lamellae; (8) behavior toward dilute iodine solutions; (9) the 

 temperature at which the *' Kleister " or paste is formed and its 

 consistency ; (10) the behavior toward various reagents, as chromic 

 acid, calcium nitrate, chlor-zinc-iodide, sulphuric acid, diastase, 

 etc.; (11) the appearance as viewed by polarized light. These 

 differences in starch grains not only from different sources, but 

 even in those of the same origin, tend to show that instead of 

 starch being a uniform substance, it is made up of several sub- 

 stances, these occurring in varying proportions but appearing 

 to be more or less definitely arranged. ' 



The author may briefly state that he conceives the reserve 

 starch grain to be the direct product of the polymerization of 

 soluble carbohydrates of either the glucose or cane sugar group, 

 together with the abstraction of water. This process is carried 

 on under the influence of an organized body — either protoplasm, 

 or a plastid, or both. The products thus formed consist of two 



" The terms " hilum " and " nucleus " have been employed to distinguish the cen- 

 tral or excentral marking, around which the lamellae or layers of the grain are arranged. 

 These terms, however, are open to criticism, inasmuch as they are employed for 

 another and specific purpose. The expression "point of origin of growth" seems to be 

 better on account of its being less confusing, and is moreover descriptive and accurate- 



