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



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

 Malpighian cells. The cells are 22 fi long, each containing one 

 or more chromatophores. A small intercellular space occurs 

 below the Malpighian cells. Longitudinal striae of the 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. (Spiesia, 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. (jS. Lamberti, Pursh, Lamb.) 



PI. XIII. f. 4. 



Testa and endosperm 170-175 fx. 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 /n 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 ceU-waU takes on a darker blue color. Cells contain 

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



Osteosclerid. 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. 



Endosperm. 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. 



