. GAMETOPHYTE AND SEX ORGANS OF REBOULIA 
He HEMISPHAERICA 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 276 
: ARTHUR W. Haupt 
(WITH TWENTY-ONE FIGURES) 
The Marchantiales represent a very natural group of liverworts 
whose evolutionary tendencies are more obvious and striking than 
those of any other order of Bryophytes. The characters which 
distinguish them from the Jungermanniales are remarkably con- 
stant, and yet the structural changes which one meets in passing 
from the lower to the higher forms are represented by an almost 
complete series of intergrades. In order to determine the phy- 
logenetic relationships of the little investigated genus Reboulia, 
the present study was undertaken. 
»| According to ScHIFFNER (7), Reboulia comprises 2 species: 
one confined to Java, and the other, R. hemisphaerica, a poly- 
morphic species; cosmopolitan in distribution. STEPHANI (9) 
recognizes only R. hemisphaerica as a single polymorphic species, 
including as synonyms several other forms which various 
authors have raised to specific rank. Cu. and R. Dovutn (3) 
have: described 2 new species from France and other parts of 
Europe which they have named R. occidentalis and R. Charrieri. 
These are distinguished from R. hemisphaerica chiefly on the basis 
of the size and wall markings of the mature spores, the size and 
number of lobes of the female receptacle, and the position and 
behavior of the male receptacle. The latter forms two groups 
which come to occupy marginal positions on the thallus instead of 
remaining undivided and median as in R. hemisphaerica. The 
writer has observed this in rare cases in R. hemisphaerica, and if 
the small size of certain parts be explained on the basis of impover- 
ished vegetative conditions, there seems to be little justification 
for the establishment of these 2 new species. 
SCHIFFNER (7) divides the Marchantiaceae into the 3 sub- 
families, Corsinioideae, Targionioideae, and Marchantioideae. 
61] [Botanical Gazette, vol. 71 
