34 HISTOLOGICAL NOTES. 
On the Adventitious Roots of the Cherry-laurel. 
B 
to the gelatinous degeneration of the walls of the cells at the growin 
nt. This view turns out to be quite correct, as it has also been ob- 
some plants the cells of the pileorhiza do not separate, but always remain 
attached, as in Lemna, Pistia, and Cuscuta ! 
* 
proper to the stem and those runnine to the leaves. In other dicotyledo- — 
us ; however, these bundles are often separate, and if instead of — 
forming a cylinder with a ring of cambium, the individual bundles remain — 
separate, the stem will resemble very much the stem of a monocotyledon. - 
In dieotrietone, according to Sachs (Lehrbuch, p. 542 
&) dà other stems the leaf-bundles unite and leave a closed cambium ring; 
s to grow, and a new one forms outside, 
oie and Nympheacee. Tn Piperacee, Begoniacee, and Aralia, the : 
in “es secondary bundles remain isolated, while the leaf-bundles form à 
cylinder leaving a closed cambium ring, a very interesting modification of 
ihe i a üch stems would be very puzzling to i: 
ateeont botanist, and mi ir bei in a wrong 
divisiod d bra vein ght lead to their being placed in a wr ; 
5 . à 
s ; On the Periderm of Acer campestre. t 
© young stems of Acer campestre give a very good demonstration 0 
P riderm. In the autumn the shoots of the me yp become more oF 
ss invested with a covering of cork—the periderm. On examining the 
