Staber: The anatomy of Sesban macrocarpa 629 



increased, the stereome, unequal to the strain, split up into 

 masses (figure 3). At a point 20 cm, from the root, it showed 

 forty- four groups. But just above the roots were only fourteen 

 groups, the number of cells composing each being considerably 

 less than higher up in the stem. But added to these and serving 

 as mechanical tissue were the scattered fibrous cells with the 

 cellulose lining and lignified walls, or bast fibers, * which, as men- 

 tioned above, formed the transition stage between the mechanical 

 cells of the root and stem. 



Enclosing the stereome was a well-defined endodermis (figure 

 In transverse section the cells were longer than they were 

 wide. This endodermis was not constant throughout the stem. 

 It was very definite in the younger portion, but was lacking in the 

 old. The amount and relation of the starch to the sheath varied 

 in the different sections. At a point 94.8 cm. from the base the 

 starch was confined to the endodermis, where it occurred plenti- 

 fully. Ten cm. lower, hardly any starch appeared. A cross sec- 

 tion taken at 73 cm., or 1 1 cm, lower, showed very few starch 

 grains scattered in the endodermis. Still lower down, or at 57 

 cm., the amount of starch in the endodermis was somewhat 

 greater ; while at 40,5 cm., no starch was found in the sheath, but 

 considerable in the leptome, some in the medullary rays and some 

 in the periphery of the pith. Still older portions showed the 

 endodermis lacking starch. But in the leptome, in the medullary 

 rays and in the periphery of the pith, there was a great abundance 

 of it. Therefore the amount of starch varied according to the age 

 of the stem. In the young or actively growing region practically 

 none or very little starch was stored, whereas in the older portions 



large quantities were kept for reserve material until the time for 

 fruiting. 



According to Solereder f one often finds as characteristic of 

 the Papilionaceae, glandular cells having a wide lumen and con- 

 taining brown albuminous substance. For a long time these ves- 

 sels were considered laticiferous, but the researches of Trecul X 

 showed conclusively that the contents were tannin. He classifies 



♦Tschirch, Angewandte Pflanzenanatomie I : 295. 

 t Solereder, Anatomic der Dicotyledonea 28S. 

 t Trecul, Compt. Rend. 60: 225. 1865. 



