208 The Botanical Gazette. [April, 
by themselves the epidermis cells do not give us any hint in 
this direction, except that they seem to differ from those of 
an ordinary root. The fact that the cells are different in 
size and shape, viz., that there are bands of elongated cells 
in alternation with other bands of shorter, more irregular ones, 
only indicates that the elongated cells may have been situ- 
ated above some fibro-vascular bundles. This is a very get- 
eral feature of the mono- and dicotyledonous plants, and 
such structure is also known from the cryptogams. But 
whether it is a stem or a leaf can not yet be made out. 
The next question is as to the nature of the stomata. Mr 
Knowlton states that ‘‘these are the most remarkable feature 
of the plant, because the guardian-cells [séc] are quite irregu- 
lar in shape and appear to vary in number from four to SIX 
It is true that the number of guard-cells about a stoma is not 
always limited to two, and that the stomata of Equisetum 
and Marchantiahave more. But as such stomata are entirely 
different from those figured by Mr. Knowlton, we have 
copied an illustration of the epidermis with stomata of Mar 
chantia (fig. 5), taken from Sachs. 2 
Mr. Knowlton also states that the ‘‘ouardian-cells are of 
course below the epidermal-cells.” Combining now the acts 
is situated below the epidermis. We will compare this & 
scription with Mr. Knowlton’s drawing (fi 
figure 6, which we have copied from Van Tieghem. 
copy shows only a part of the original illustration s0 % : 
give the aspect of the stomata of Nerium Oleander. 
rounded by the pneumatic tissue. But we fail to find any . 
we begil 
then some roundish o 
i i >). which are 
rounded by four or si penings (if not cells?), w 
; iliat 
x Cells, a structure that is very fam! 
2 pe a 
eg Julius: Vorlesungen iiber Pflanzen-Physiologie 83. ig. D. inet 
8 ’ H * 
Van Tieghem, Ph.: Traité de Botanique 60, fig. 33. Paris. 1884 
