274 BOTANICAL GAZETTE [APRIL 
rhizoids which are doubtless the homologues of the characteristic 
tuberculate ones of the typical Marchantiacee. 
It is the structure and arrangement of the sexual organs, however, 
which prove the close affinity of Monoclea with the Marchantiaces. 
Both Leitgeb and Ruge noticed the extraordinary resemblance of the 
male receptacle to that of such forms as Conocephalus or Fimbriaria, 
and Ruge’s figures show that the development of the antheridium 's 
thoroughly typical of the Marchantiacez, although he makes no men- 
tion of this fact in the text. 
The origin of the archegonia is exactly as in Targionia, and | have 
found that there are six rows of neck-cells, as in the Marchantiace®, 
instead of the five regularly found in the typical Jungermanniacee. 
It seems strange that Ruge did not recognize the obvious marcha 
tiaceous character of the reproductive organs, but he passes over this 
point without comment. Schiffner® places the genus in the ei 
manniacez, near Pallavicinia and Symphyogyna, although admitting 
marked differences in the character of the sporogonium. 
In regard to the exact position ‘of Monoclea, it will not be po 
sible to decide until more is known of the development of te 
embryo. At present it seems to approach Targionia more nearly pit 
any other genus. The resemblance to Dumortiera is probably st 
superficial, and simply indicates a similar adaptation to similar sem! 
aquatic environment. 
We may safely conclude that the affinities of Monoclea 
lower series of Marchantiacee, perhaps the Targioniez, 
archegonia are borne directly upon the unmodified thallus, 
definite receptacle is developed. The absence of lacunae, aa sade 
the simplification of the rhizoids and ventral scales, are oa eo 
question secondary, as they are in Dumortiera, where, nee og: 
are with the 
where the 
and no 
suppose that the two genera are closely related, as Du! 
undoubted relationship with the higher Marchantiee, ial 
where both antheridia and archegonia are borne upo? sah 
fied receptacles which are compound, representing 4 the lower 
Monoclea may be supposed to bear the same relation is Doves 
Marchantiacee that Dumortiera does to the higher OR" 
Houcuton Camppe.t, Stanford University. = 
8 ENGLER and PRANTL, loc. cit. 
