2GS DIFFERENTIATION AND SPECIFICITY OF STARCHES. 



Cicer, Pisum, Ervum, Orobus, etc. {LeguminoscB.) Cotyledons. — Among the simple centric-oval 

 grains are foimd compound grains which consist of 2 to 4 usually equal components which 

 are more or less regularly arranged. Separated-grains oval, rarely rounded, with 1 curved 

 surface and 1 to 3 small pressure facets; lamellae none, or few and delicate; with an oblong 

 compressed hilum; after drying, a distinct median slit is mostly visible from the narrow 

 aspect, and radial fissures from the broad aspect. Size of the compound grains of Pisum 

 satimim Linn, about 75|U. Size of the separated-grains about 5Qfi. Size of the separated- 

 grains in Ciccr arietinum Liun. about 19^. 



Amphicarpoea monoica Nutt. {LeguminoscE.) Dry cotyledons. — Compound grains consisting of 2 

 to components which are usually almost equal. Size about 14/t. Separated-grains; size 



3 to lOyu; the large and oval forms have instead of a hilum a small cavity about one-half 

 eccentric. Also simple eccentric-conical grains are found. 



Type 15. Grains Compound, Components Few and Unequal. 



From 2 to 10 unequal components united into a compound grain; divided by fissures and at 

 maturity falling apart into separated-grains which have one curved surface and one or more flat- 

 tened pressure facets. These compound grains for the most part arise from the cutting off of angles 

 and edges. For this reason they frequently consist of several small components piled upon one 

 large one, or even of two or more large ones which have small ones at their line of union. They 

 rarely occur alone, but usually are mingled with simple grains or compound grains of equal compo- 

 nents, the latter being formed by division of the hilum and thus are related to tyiJe 14. They may 

 have their origin by a number of simple grains in one chloroplast uniting into a compound one, the 

 latter frequently, partially or entirely, retaining its green color. 



Chara fcetida A. Braum. (Algas.) Fresh nodes of the stem {basal nodes of the lohorled branches). — Com- 

 pound grains spherical and oval to rod-shaped; about 4 times as long as thick; consisting of 

 2 to 12, rarely 20, unequal components; green at first, colorless later. Length about 34/j, 

 thickness about 23/u. Separated-grains polyhedral, usually with 1 curved surface and 1 to 



4 pressm-e facets; 1 to 2 times as long as broad; no lamellae; usually without a hilum. Size 



5 to 17ai. Starch-gTains arise within the chloroplasts. 



Ptei'idophyta. Green parts. — Compound grains spherical, arising within the chloroplasts and con- 

 sisting sometimes of 2 to 5, sometimes 2 to 10 or more, components which are more or less 

 equal, and usually lie in one plane, and are gxeen to colorless. Occasionally with irregular 

 accretions of fatty oil. Some simple grains are also present. 



Opuntia coccinellifera Mill. {Cactaceoe.) Green paiis. — The simple grains are somewhat disk-shaped; 

 size about 16;u. The compound ones, size about 24//, consist of 2 to 5 components; the size 

 of a component is 3 to 12/i. 



Begonia sp. (Begoniaceoe.) Leaves. — Compound grains consisting of 1 to 3, rarely 16, components; 

 size 24/i; part-gi'ains 3 to 12/i. 



Nerium oleander Linn. {Apocynacea:.) Young leaves. — Simple grains almost rounded; size usually 

 about Q/i. Compound grains, of 2 to 4 and 5 components; size abut 9//. 



Nephrolepis exaltata Schott. {Polypodiacew.) Base of the frond. — Compound grains of 2 to 8 and 

 more components; size 31ju. Size of the components 3 to 16/i. 



Chara stelligera Bauer. (Algce.) Dry stellate bodies. — These compound grains, which approach the semi- 

 compound type, are disting-uished by having 1 to 30 to 70, and occasionally 100, small compo- 

 nents adhering to one large rounded one. These contain one or usually several hila (or as a result 

 of drying, small hollow spaces are found instead of the hila), and thus they become semi-com- 

 pomid, frequently showing distinct concentric lamellae (around the mathematical center), and 

 short radial fissiu-es in the interior. The smaller components have a small central cavity, but 

 neither lamellae nor fissm-es. They are found either at one or the two opi)osite sides of the large 

 component, and when 2 to 5 are joined they lie in one row, thus forming a border. When present 

 in larger numbers, they lie in one flat plane and form a sort of shell which covers one-sixth to 

 two-thirds of the circumference of the large component. This shell can often be loosened by 

 means of pressure as well as by the expansion of the larger component, which in the center has 

 from two to several lamelUe. Size of the complete compound grain about 70 to So/i; of the large 

 components 55 and 70ju; and of the small adhering components 5 to 13 and 20/j. 



