CHIEF FORMS AND CLASSIFICATIONS OF STARCH-GRAINS. 71 



A. Monarch Starch-Grains. Continued. 



discernible Icucoplasts. In certain of the leucoplasts several starch-granules 

 arise almost simultaneously, the number increases although it varies until cell 

 division is complete. The chromatophores are rounded at first, and remain so as 

 long as there is no pressure on them. When the starch-bearing chromatophores 

 have attained about half of their ultimate diameter they begin to flatten against 

 one another, since they are rather crowded in the cytoplasm. The starch-gran- 

 ules, which are angular and much crowded when first recognized, gradually 

 liccome more and more regular, since they check each other equally in growth. 

 Distinct liimelkB are not present in the developing grain, since at first they are 

 angular and corroded; and only a feebly refractive hilum, which corresponds to 

 the earliest corroded stage of the grain, can be observed in the mature grain. 



B. Complex (Di- to Poly-arch) Starch-Grains. 



It can not be readily demonstrated that complex grains, like certain grains, for example, of 

 Pellionia, are descended from adelphous grains. It has, however, proven that all 

 plant parts in which complex grains are present also at times develop adelphous 

 starch-grains which correspond entirely with the central lamellae of the complex 

 grains. Furthermore, gradations between the adelphous and the similar complex 

 forms can be found. Additional proof of the connection between adelphous and 

 complex starch-grains is the fact that plant parts which produce few and irregular 

 adelphous grains likewise have relatively few and irregular complex grains in 

 their cells. In the storage scale leaves of Adoxa it is noticed that numerous 

 adelphous grains form at first, but only complex grains are present later, and the 

 layers of the latter resemble those of the former. After the two diadelphous 

 starch-grains found in Pellionia have attained a certain size in the chloroplast, 

 the chloroplast substance is entirely forced out between the contact surfaces of 

 the grains, or is cut off from the remaining mass of the chromatophore by the 

 growing trichites, so that no more starch-substance is stored in the region of the 

 contact surfaces. If the chromatophore mass between the flattened surfaces be- 

 comes inactive or disappears, the two starch-grains again grow into diarch form. 



Muter's Classification of Starches.* 



This classification, which is based upon histological and polariscopic peculiarities, is 

 characterized by the designation of each group by some important type of starch : 



Potato group. Oval or ovoid granules, showing hilum and concentric rings clearly; cross 



and colors with selenite usually distinct. 

 Legume group. Round or oval granules, hilum marked, rings faint, but rendered visible 



in cases by chromic-acid solution; cross and colors feeble. 

 Wheat group. Rountl and oval granules, hilum and rings generally invisible; feebly marked 



cross and colors. 

 Sago group. Truncated granules, hilum distinct, rings faint; cross and colors usually faint. 

 Rice group. Polygonal granules, hilum distinct, rings faint; cross and colors usually faint. 



Kraemer's Classification of STARCH-GRAiNs.f 



This classification includes the starches of some of the more important vegetable 

 drugs, together with a few commercial starches, and is based upon morphological and 

 other characters. 



A. Simple spherical grains. 



(a) Not more than 5ii in diameter: Cimicifuga, Cypripedium, Frangula, Hydrastis, Leptandra, 

 Piper, Prunus virginiana, Quassia, Quercus alba, Rhamnus purshiana, Spigelia, 

 Viburnum opulus, and Viburnum prunifolium. 



Organic Materia Medioa; quoted by Leffraann and Beam, Food Analysis. 1906. 

 t Botany and Pharmacognosy, Philadelphia, 1907, 698. 



