206 THE UNIVERSITY SCIENCE BULLETIN. 



These layers are therefore concluded to be inner layers of the bast 

 which are not completely lignified, but still have cellulose in them. 

 With a polarizer, as well as potassium iodide-iodine or chloro- 

 iodide of zinc, starch grains in the starch sheath are shown, but no 

 crystals. Irregular broken spaces are often found in the center of 

 the pith of the petiole. These do not seem to be mucilage chan- 

 nels. 



Stem. The stem does not show distinct annular rings, even 

 though secondary thickening is apparent. The phloem is rather 

 extensive (figs. 8, 9, and 10), and is filled with food materials. 

 Fig. 9 shows three of the smaller bundles in a stem and fig. 10 a 

 longitudinal section of one of the larger bundles. Sieve plates can 

 not be seen. The older portion of the stem has thick cork. This 

 cork tissue gives the suberin test with Sudan III and the lignin 

 test with phloroglucin, as if the suberized membrane were partially 

 infiltrated with lignin. 



Root. The root shows annular rings better than the stem. 

 Between the rings of water tubes are rings of wood parenchyma 

 cells, which are unlignified, as are also the wood fibers. The water 

 tubes are the only part of the root which is lignified. (Fig. 12.) 

 The phloem is great in extent. (Figs. 11 and 13.) The older 

 portion of the root has cork similar to that of the stem. 



Inflorescence. The peduncle is, like the petiole, made up of 

 many bundles which are to supply the pedicels and bracts at their 

 bases. As these are opposite, the peduncle contains four less 

 bundles above their separation than below. There is relatively 

 more bast in this portion of the plant than in any other. There 

 are one or two rows of lignified parenchymatous cells, making a 

 ring connecting the bundles, near the outer edge of the xylem. 



The flower is a typical one of the tribe Galegeae of the Legumi- 

 nosse. The pod is curved, with a partition extending in from the 

 convex side and separating the two cells. In the center of the 

 tissue of the pod is a layer .3 millimeter thick of bast fibers which 

 encircle it, thus making it very stout. 



BIBLIOGRAPHY. 



Alsberg, C. L., and Black, O. F. ('12). Laboratory Studies on the Rela- 

 tion of Barium to the Loco-weed Disease. U. S. Department of Agri- 

 culture, Bureau of Plant Industry, Bulletin No. 246, part II. 



Crawford, Albert C. ('08). Barium, a Cause of the Loco-weed Disease. 

 U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 

 No. 129. 



