166 Trans. Acad. Sci. of St. Louis. 



with A. mexicanusm having most of the yellow pigment in the 

 Malpighian cells. The cells are 22 /u. long, each containing one 

 or more chromatophores. A small intercellular space occurs 

 below the Malpighian cells. Longitudinal striae of tiie osteo- 

 sclerids are not marked. Nutrient layer agrees with that of 

 the last species. Endosperm is well-developed laterally. All 

 of the cells of the endosperm contain protein. Embryo as in 

 A. mexicanus. For complete reactions see Table A. 



OxYTROPis, DC. (/^S2>^esm, Neck.) 



Anatomically this genus is closely related to Astragalus. 

 Endosperm is present in the species studied. One species was 

 studied by Chalon. 



Oytropis Lamberti, Pursh. {8. Lamherti^ Pursh, Lamb.) 



PI. XIII. f. 4. 



Testa and endosperm 170-175 ^. This, the so-called loco 

 weed, is said to cause disturbances in animals, but alkaloids 

 have not been found in the seed or any other part of the 

 plant. 



Malpighian. Cells 40-42 /i long. Cuticle somewhat un- 

 even ; the narrow well-marked cuticularized layer colors blue 

 with chlor-iodide of zinc; the light line occurs below the 

 cuticularized layer, and this also colors blue ; the remainder 

 of the cell-wall takes on a darker blue color. Cells contain 

 an abundance of pigment, tannin, and some plastic material. 



Osteosderid. Cell-walls thickened, not prominently I- 

 shaped, but with an elongated intercellular space. 



Nutrient. Layer consists of thin-walled elongated cells, 

 from ten to twelve rows. Pigment more abundant in lower 

 than in upper part. Walls color blue with chlor-iodide of 

 zinc. 



JEJndosperm. The aleurone layer consists of thick-walled 

 cells; the underlying thick- walled cells of the reserve cellulose 

 become mucilaginous on the addition of water. The internal 

 part consists of thick-walled, elongated cells. The cells con- 

 tain protein. 



Embryo. Cells of the first row smaller, with thick exterior 

 walls; cells below not so compact and with thinner walls. 



