140 



THE SCIENTIFIC FEEDING OF ANIMALS 



The following key will assist in the determination of the origin of starch grains. 

 Since some of the characteristics are common to several varieties, a sharp distinc- 

 tion is not always possible. 



I. Starch grains simple, bounded by curved surfaces. 



A. Disk-shaped or globular, without distinct lamination. 



a. Grains mostly lens-shaped, large and many small sizes ; few transition 



forms: Wheat, rye, barley starch. 



b. Grains globular with nuclear vacuole: Peanut starch. 



B. Oval and elongated, usually with nuclear vacuole and laminated. 



1. Concentric nuclear fissure and lamination. 



a. Grains bean or kidney shaped, nuclear vacuole fissured : pea, bean, 



vetch starch. 



b. Grains irregularly sinuate, flask-shaped, with long, concentric nuclear 



fissure and indistinct lamination : Acorn starch. 



2. Eccentric nuclear vacuole and lamination. 



a. Grains large, conchiform, lamination very distinct, eccentric: Po- 



tato starch. 



b. Grains irregularly sinuate, lamination and nuclear vacuole eccentric : 



Horse-chestnut starch. 



Fig. 70. Disk-shaped starch. 



Fig. 71. Corn cockle starch. 



Grains simple or compound. Individual grains (broken) polyhedral, entirely 

 or partly bounded by plane surfaces. 



1. Composed of simple small grains and of compound large spheroidal grains 



and parts of grains: 



a. Regular and with sharp edges, often with nuclear vacuole, polyhedral : 



Rice starch. 



b. Edges rounded, no nuclear vacuole, many sliapcs : Oat starch. 



2. Composed of simple and of large irregular compound grains : 



a. Sharply defined borders, rounded or polyhedral, nuclear vacuole fis- 

 sured : Corn starch. 



