176 Trans. Acad. Sci. of St. Louis. 



numerous and very plainly marked when treated with chloral 

 hydrate. In surface view they appear as short canals much 

 as in Arachis. Specimens treated with potassium hydrate and 

 then mounted in glycerine are colored reddish. The whole 

 Malpighian layer on the addition of iodine colors brown 

 except the light line which remains as a translucent zone. 

 Ferric chloride, when allowed to act for some time, colors the 

 walls and contents bluish-black, in strong contrast with the 

 cells below. 



Osteosderid. Cells 10-14 /* long, thick-walled. Inter- 

 cellular spaces elongated ; frequently the cells are very widely 

 separated. Cells contain protein grains. Walls are not 

 greatly thickened, not nearly as much as in Lespedeza. 



Nutrient. This layer is much compressed, reaching its 

 greatest development in the hilar region. The cells are elon- 

 gated and thin-waUed. Contain pigment and a little tannin. 

 Lignified only where the vascular elements occur. 



Endosperm. This consists mainly of one layer of cells, 

 the aleurone, but an internal layer, made up of elongated 

 thick-walled cells, may be made out in some parts of the seed. 



Embryo. The epidermal cells are smaller than those below ; 

 exterior walls thickened. Palisade cells on the interior face 

 of the cotyledon arranged rather compactly. All of the ceUs 

 contain protein and a great deal of fat, also simple and com- 

 pound crystals of calcium oxalate, one or occasionally several 

 in nearly every cell. — (Sapulpa, Indian Terr., B. F. Bush, 

 No. llf.) 



Arachis, L. 



Several accounts have been given of the testa of the pea- 

 nut. The earliest account of the genus is by Chalon, who 

 gave the essential facts with reference to its structure. 

 Schleiden and Vogel gave an account of the cotyledons. 

 Later Harz, and Mattirolo and Buscalioni, gave an account of 

 the structure of the seeds. Pfaefflin, who studied more espe- 

 cially the tracheid island, also describes other parts of the 

 testa. Godfrin discusses the comparative anatomy of the 

 cotyledons. In many respects the genus closely resembles 

 Stylosanthes. The protective features are replaced by the pod 



