Pammel — Anatomical Characters of Seeds of Leguminosae. 113 



This layer has frequently been called the pigment layer, 

 because of the unusual amount of pigment found here. The 

 general term anthocyanine (Harz 99, 2; 563) has been 

 applied, and the pigments of several species have received 

 special names. This has been referred to under Malpighian 

 cells. The pigment occurs not only in the cell- wall but in 

 the cavity as well. The coloring matter is formed just pre- 

 ceding maturity when the final products, starch and other 

 reserve materials, are forming. In seeds allowed to mature 

 on the plant this proceeds progressively, but when they are 

 separated it takes place rapidly ; in the course of a few minutes 

 the color begins to show in the cells. In sections of Mucuna 

 pruriens it rapidly diffuses to the neighboring cells of the coty- 

 ledons. The pigment is but slightly soluble in cold water. 



Tannin is closely associated with the pigment, and by some 

 has been considered to be a part of it. It likewise occurs in 

 both the cell- walls and cavity. Some tannin has been found 

 in this layer in all the seeds studied, although the quantity is 

 small in some cases. 



In some cases protein matter may be made out. Alkaloids 

 like cytisin, robinin, cumarin, and others occur. These also 

 occur in other parts of the seed. In Melilotus seeds the 

 cumarin is evident although the seeds have been kept dry 

 for years. 



In some cases^ calcium oxalate is common in the immature 

 seed, especially in the hilar region ; but it is always transitory 

 and disappears when the cells lose their function of supplying 

 nutrient material. The general structure and microchemical 

 reactions are shown in Table D. 



Mycotic Layer. 



In Phaseoleae a well-developed layer of compact cells 

 occurs underneath the nutrient layer. The cells are elon- 

 gated, thick-walled, and rich in protein. These cells resemble 

 the short, thick-walled hyphae in the sclerotia of some fungi. 

 I found this layer well developed in Phaseolus multijloi'us 

 and other members of the genus as well as in Wistaria ^ 

 It is figured and briefly described by Tschirch and Oesterle 

 (267), but earlier by Haberlandt (83). 



