1903] BRIEFER ARTICLES 227 
photograph. From sections made through the growing point it could 
be seen that in the younger parts the air chambers were about as per- 
fect asin Marchantia. Such a chamber is shown in fg. 2. It will be 
noticed that the pore at the top is not so definite as in typical cases, 
but in every other way the chamber is perfect. There are several cells 
projecting from the 
floor, which contain 
chromatophores and 
are no doubt the 
homologues of the 
filaments filling the 
chambers of Mar- 
chantia, as remarked 
by Leitgeb. These 
papillae are not at 
all abundant, but are 
— Dumortiera hirsuta, Two thalli of natural scattered here and 
size; ae a photograph. 
there, and often per- 
sist in the older parts. They were never found to form chains of 
cells, as in more complex thalli. As they become further and further 
i 
G. 3.—The same. Wall of 
Fic. 2.—The same. Section through an Fic 
air chamber. X 246. chamber an older part with a few 
cover cells still attached. X 2 
removed from the growing point, the air chambers become less perfect, 
the roof cells become torn apart, and many are thrown off, until only 
a few-remain around the upper edge of the wall cells (7g. 3). Finally, 
on the older parts, only the basal cells of the partition are left to form 
the reticulations seen in fig. 7 
It will be seen that we have in D. Airsuta chambers and papillae 
