5=^4 TRANS. ST. LOUIS ACAD. SCIENCE. 



Cross-sections of the seeds are shown on PL xii., p. 568, figs. ly 

 2, and 7. As the seeds are extremely hard and brittle, they 

 were placed in water for a time ; in that way it was thought 

 good sections could be obtained. An examination of such 

 material showed that the white portion was transformed into 

 a mucilaginous substance. Dry sections were then cut and 

 mounted in water, then examined. The outer cells are colorless 

 and clearly stratified ; they are rounded out, and under the intiu- 

 ence of water elongate, becoming much longer than a cross-sec- 

 tion of the seed itself. In a surface-view these cells are prismatic 

 in outline. Some microchemical tests were made with the follow- 

 ing results: — A section was placed in alcohol, and potassium 

 iodide was added. The outer cells began to lengthen out, other- 

 wise no change could be observed ; but on addition of sulphuric 

 acid the cell-walls and the spirals became violet, changing to 

 blue. In no case did the iodine act on the cell-walls before the 

 addition of the acid. 



The palisade-like cells are present in all of the species studied ; 

 in some they are less developed, as in E. folygonifolia. Between 

 the palisade tissue and the outer coloi'less cells a granular layer 

 occurs ; this is present in all of the species abounding in mucil- 

 age, indicating that it has some connection with the formation of 

 this substance. The outlines of these cells are difficult to make 

 out. On the addition of iodine the granules color blue. In E. 

 Gcyeri another layer of polygonal cells is found underneath the 

 palisade-like cells of the inner seed-coat. They are radially 

 elongated cells with thin walls. This layer in both species is 

 very much compressed. In E. Gevcri the pores in the palisade 

 cells are somewhat more pronounced. 



The general outline of the seeds of the next section is shown on 

 PI. xii., figures 5-9. They are wrinkled and more or less pitted 

 The seeds of E. serpvi/ifolia, E. givptosperma^ E. maatlata^ 

 E. humistrata^ are ash-colored, while in E. Preslii they are 

 blackish. As in the last section, the outer row of cells is mucila- 

 ginous with the exception of ii. Pres/ii, already referred to. This 

 character is well developed in E. serpyllifolia^ and somewhat 

 less so in E. glyptospcrma^ nevertheless easily seen. It is less 

 developed in E. macnlata and E. humistrata. 



The roughening of the seeds in E. scrpyllifolia and E. gh'p- 



