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AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
the receptacle appears terminal. He found that the thallus usually renews 
growth and may produce one or more successive discs. Leitgeb agrees 
with Nees ab Esenbeck (25) that the female receptacle is near the male 
but on a different branch, the thallus forking just before sex-organ forma- 
tion and the one fork producing a male, the other a female receptacle, al- 
though both forks may produce the same sex organs. He gives no case 
in which both receptacles are on the same branch. 
Cavers describes features of Reboulia in several of his papers, giving 
the only general account of its morphology which we have. He noted (4) 
the explosive discharge of the sperms, as high as 5 cm. Other phases of 
Cavers' work will be cited below. 
C. and R. Douin (10) review the literature on the ''inflorescence" of 
Reboulia, especially as it relates to the sexual nature of the plant. They 
credit Boulay (2) as the only observer previous to themselves who has noted 
marginal male receptacles. They define the antheridial disc as occurring at 
the end of a ventral or " subfloral " branch, while the female receptacle appears 
at the tip of an apical branch derived from the former and seeming to be a 
prolongation of it. They regard this as a distinctive character of Reboulia— 
"aucun autre genre de Marchantiees ne possede ce caractere." Haupt 
(16) describes the early antheridium in detail. 
The Male Receptacle 
Position. The thallus arises as a ventral branch of the previous season's 
growth, growing out laterally from the midrib or, more commonly, longi- 
tudinally from beneath the base of the stalk of the female receptacle, giving 
a jointed aspect to a two-year plant (fig. i). The male receptacle occupies 
a median dorsal position a short distance behind the female receptacle 
which terminates the branch. Two successive male receptacles are com- 
mon (figs. I, 2). Occasionally two discs may be lateral to one another 
(fig. 3), and rarely a cluster of several discs may be formed (fig. 4). The 
shoot may form both male and female receptacles without forking (fig. 5), 
although usually the primary shoot forks from one to three times during a 
season (fig. 2). The male receptacle may arise before or after the time of 
forking (compare figs. 1-12). The Douins (10) used the position of the 
male receptacle as one of the characters in separating from the polymorphic 
R. hemisphaerica of Stephani (26) two new species, R. occidentalis and R. 
Charrieri, in both of which the male receptacles are marginal instead of 
median as in R. hemisphaerica. Haupt (16) found a few rare case 3 of 
marginal receptacles in this form. The writer has not found a single case 
in hundreds of plants examined. Haupt thinks there is little justification 
for the new species. The Douins' claims were based on a careful study of 
plants grown under similar cultural conditions and can not be set aside sum- 
marily. 
Form. In both the proposed new species of Douin the "primary disc" 
