200 BOTANICAL GAZETTE [SEPTEMBER 
clea is still more clearly marchantiaceous in type. The large number 
of primary transverse divisions in the young antheridium, the mode 
of separation of the primary spermatogenous cells from the wall 
cells, and the elongated pointed form of the mature antheridium are, 
I believe, not found in any of the Junger iaceae. 
The development of the archegonia directly upon the dorsiventral 
vegetative part of the thallus has, as was noted above, always been 
considered a most important difference between Monoclea and the 
Marchantiaceae, most workers having on this account compared it 
rather with the genera Pellia and Symphyogyna of the Jungerman- 
niaceae. But even in this feature Monoclea is not without counter- 
parts among the Marchantiaceae. For example, in Funicularia, 
according to LErrcEB (’79, p. 59) the archegonia are formed in 
groups of three or four, each group being sunken in a pit in the dorsal 
side of the thallus and protected by a hood-like involucre, which 
grows out over the archegonia from behind. Likewise in Corsinia, 
according to the same author (’79, p. 55), the archegonia arise acrope- 
tally in groups of eight or ten exactly as in Monoclea, and are also 
covered by a similar hood, which however seems to develop after 
fertilization. This hood may cover all the fertilized archegonia in 
one pit or there may be several hoods in the same pit, each cover | 
ing one or more archegonia. In both genera of the Targionioideae 
(Targionia and Cyathodium) the archegonia arise directly behind the 
growing point of an ordinary branch of the thallus (Lerrces ’81, 
Pp- 133 and 139, and CAMPBELL ’9s, p. 54). The two-lobed out 
growth of the thallus found here resembles in origin the involucre of 
Monoclea, though it remains quite small until after fertilization. 
It seems more probable that in the case of Corsinia the wall of the 
pit as a whole is homologous with the involucre of Monoclea, rather 
than that each of the hoods is, but the most important character which 
Monoclea has in common with Corsinia, as well as with the othet 
genera mentioned, is the development of the archegonia on 
unspecialized portion of the thallus. . 
Of the archegonium of Monoclea I have already said that . 
development and mature structure are typically marchantiaceo® 
In the very long neck and especially in the six rows of neck cells 
differs from all known Jungermanniaceae. 
