28 
REPORT ON BOTANY, MDCCCXLl : 
annular cells: fig. 8, of Epiphyllum phyllanthus ; figs. 9 and 
10, of Opuntia vulgaris ; fig. 11, of Cereus jiahelliformis. The 
chlorophyll forms, in figs. 9 and 10, an oblong substance. The 
enclosure in Bhipsalis salicornioides, fig. 7, consists of seyeral 
cells placed in a circle, and the internal curved cells are also 
seen grown together into a small ring. The stomata of the 
Hahea pugioniformis are also of the same form, but a veil, 
consisting of a deposited matter, which wholly or partially over- 
spreads the stomata, is also frequently seen in them, although 
not always. Fig. 3, of the fourth table, exhibits a quite free 
and a half-veiled stomate ; fig. 4 an almost entirely covered 
stomate. This veil, or rather obstruction to the stomate, is seen 
still more distinctly in the stomata on the leaves of the Coni- 
ferce. Table 5, fig. 6, of Cunningliamia sinensis; fig. 7, of 
Picea excelsa ; fig. 8, of Picea alba. Free and obstructed 
stomata, at one and the same time, are found on the leaves of 
Araucaria excelsa, fig. 2, and of Araucaria imbricata, fig. 4. 
On boiling the leaves with water, the stomate becomes free, as 
may be seen in the stomate of Araucaria imbricata, fig. 5. 
Boiling them with spirit of wine does not aftect this so readily. 
I did not succeed at all in doing it. I have always entertain- 
ed doubts, that the stomata were the air holes of plants, and 
consequently the organs of respiration. I do not find a dis- 
tinct connection between the stomata and the chasms in the 
cellular tissue of the leaves. It always appeared strange to 
me, that organs of so distinct a structure should only lead to 
mere chasms in the cellular tissue ; and the obstructing and 
covering matters which they produce, have finally induced me 
to consider them as organs of secretion. But I must leave the 
matter in doubt, for I confess, that I should not know what 
to say, if I was to be asked, “ What secretions are formed 
by stomata in which such obstructions are not observed F’ 
Certainly much has been said about open and closed stomata. 
I myself have said much, and it is very possible that the ob- 
structed stomata have been taken for closed ones. 
* Mention will be made of a contention between Dutrochet and 
Delile respecting this subject, in the Annual Report for 1841. 
420 
