198 DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



A. Grains Simple — continued. 



I. Centric — continued. 



Type 2. Lenticular. When the grain is free both hilum and grain are rounded; grains 



compressed;* sometimes circular or ovoid; sometimes triangular or quadrangular. 

 Type 3. Oval. When the gi'ain is free both hilum and grain are oval to lanceolate-oval; 



occasionally kidney-shaped or somewhat curved; when on end they appear circular 



or somewhat comjiressed. 

 Type 4. Spindle-shaped. Grain linear or lanceolate, tapering towards the pointed ends, 



or of equal-width blunt ends; when on end they ajipear almost circular. 

 Type 5. Bone-shaped. Grain elongated and compressed from the narrow aspect, but 



linear spindle-shaped from the broad aspect, with enlarged laminated ends. 



II. Eccentric. Hilum usually more or less removed from the mathematical center of the grain; 



lamellae coarsest and finest at opposite ends of the grain, respectively. 

 Type 6. Inverted cone-shaped. Grain on end almost circular; more slender at the hilum end. 

 Type 7. Cone-shaped. Grains on end almost circular; decidedly thicker and broader at 



the hilum end. 

 Type 8. Wedge-shaped or compressed. Grain compressed,* of equal thickness throughout, 



or thicker but narrower at the hilum end than at the distal end. 

 Type 9. Rod-shaped. 



III. Grains simple and structure obscure. 



Type 10. Structure 7wt fully developed or not identified, owing to diminutive size of the grains. 

 LamelliE, hila, cavities, fissures, and clefts seldom observed. 



B. Grains Semicompound. 



Type 11. Grains semicompound. The component part-grains are enveloped by a com- 

 mon substance. 



C. Grains Compound. The component part-grains not enveloped by a common substance. 



I. Composed of fused part-grains. 



Type 12. Composed of fused part-grains. The part-grains are not separated by fissures, 

 and even different grains may b(; fused with one another. 



II. Composed of separated part-grains. The part-grains separated by fissures. 



Type 13. Grains in 1 or 2 rows. From 3 to 11 components arranged in 1 or 2 rows. 

 Type 14. Equally divided grains of few components. From 2 to 10 or more almost equal 



sized part-grains which, when separated, have one curved surface and one or more 



pressure facets. 

 Type 15. Unequally divided grains of few components. From 2 to 10 or more unequal 



sized, firmly united part-grains, which when separated have one curved surface and 



several flattened pressure facets. 

 Type 16. Multiple grains. From 20 to many thousand firmly united part-grains which, 



when separated, are covered with pressure facets. 

 Type 17. Hollow spherical grains. The part-grains are arranged in a spherical layer, as if 



a globular shell had been divided radially. 



For further details of the characteristics of the various types, see as follows: Type 

 1, page 198; type 2, page 203; type 3, page 207; type 4, page 212; type 5, page 213; type 6, 

 page 213; type 7, page 214; type 8, page 221; type 9, page 229; type 10, page 232; type 11, 

 page 251; type 12, page 252; type 13, page 254; type 14, page 255; type 15, page 268; 

 type 16, page 273; type 17, page 293. 



Type 1. Grains Simple, Centric, Spherical. 



Grains spherical or oval-spherical, and more or less polyhedral when crowded. Ililum in 

 center, spherical. Lamellse of equal thickness; striae of the dried grain radiate in all directions. 

 As far as known, Nageli states, these grains exist only in seeds. In the other parts of the plant, the 

 underground parts for example, spherical grains with a central hilum may occur. Judging from their 



* Niigeli, in his descriptions, uses the words zusamniengedriickt (compressed) and abgeplattet (flattened), but 

 since they are both ai)plied to the efTect of pressure from above they may be regarded as synonymous, and this has 

 been adopted at times in the translation. 



