384 BOTANICAL GAZETTE [DECEMBER 
rays (fig. 17, PR) are narrow, mostly of a single row of cells, com- 
pressed radially, and filled with starch. The protohadrome vessels 
are readily seen in the center of the root, surrounded by strata of 
thick-walled conjunctive tissue; no pith is developed. 
STEM 
The young shoot, examined in the early spring, is densely 
covered with hairs, especially glandular. Unicellular, pointed 
hairs are also common, and these occur in clusters of from two 
to fifteen, or even more. The cuticle is thick, smooth, and the 
epidermis is thick-walled. During the fall the epidermis is replaced 
by a hypodermal cork of heterogeneous structure, thin-walled 
strata alternating with thick-walled. This cork is developed from 
the hypodermal stratum of a collenchyma. Inside the collenchyma 
is a broad, compact, thin-walled parenchyma, filled with starch 
and large aggregated crystals. Two concentric bands of stereome 
are developed in the inner part of the cortex. There is no endo- 
dermis, and the stele shows a continabis zone of leptome, inter- 
spersed with cells containing singl iccrystals. The cambium 
is well represented, and in the hadrome the porous vessels are 
remarkably thick-walled. Cells containing single crystals occur 
also in the hadrome. The medullary rays are narrow, mostly of a 
single row of cells, containing starch. There is a relatively thick- 
walled pith, porous, filled with starch and aggregated crystals, and 
becoming soon septate as in Juglans regia and Pterocarya, as 
mentioned by SOLEREDER. A corresponding structure is exhibited 
by the old thick branches, but in these the stereome occurs in a 
larger number of concentric bands, twelve or even more. The pith 
also is here divided by transverse septa. 
Finally may be mentioned that the internodes of the young 
seedling are perfectly glabrous; and a cork is developed from the 
hypodermal layer of the cortex, or from the stratum inside this; 
both cases may be observed in the same section. There is no 
collenchyma in these internodes during the first season, and the 
cortex is thin-walled throughout, destitute of starch and crystals. 
Inside the barely distinguishable endodermis are four or five layers 
of thick-walled stereome, forming arches, more or less continuous 
