354 Clit ting. — On Androgynous Receptacles in Marchantia. 
Leitgeb ( 12 ) confirms Goebel’s results, and also points out that the 
organ has four rays as usual, and that two of these are male, two female. 
He also grew plants which were producing androgynous fructifications, and 
in the following year another crop of androgynous receptacles was formed— 
an extremely interesting observation, the significance of which will be 
discussed later. Leitgeb also mentions that Schmidel and Bischofif have 
observed androgynous Preissias. He holds the opinion that the andro¬ 
gynous condition is caused by the sexual differentiation being delayed 
until the formation of the branches which bear the sexual organs instead 
of taking place in the vegetative portion of the thallus. He gives some 
interesting facts concerning the distribution of male and female gameto- 
phores in Reboidia in support of this view. In this genus the male and 
female receptacles bear a relationship to each other similar to that of the 
male and female branches on the Preissia androgynous gametophores. 
Mention is also made of the relationship of the gametophores to the 
ordinary vegetative branches in Marchantia, 
Miss Townsend was not aware of the work already done on Preissia 
commutata. She expresses the opinion that the gametophore of the 
androgynous Preissia was primarily an archegoniophore, and it is to be 
presumed that she therefore thinks the development of the antheridia 
on the structure to be secondary. She does not record any correlation 
between the lobes and their sex. The gradual development of complexity 
in the arrangement of the sexual organs in the Marchantiales is described, 
and the question whether the hermaphrodite condition recorded in Preissia 
is to be regarded merely as abnormal or as a reversion to an earlier type 
is discussed. It is suggested that the latter is the more likely explanation, 
and the different arrangements of the gametophores in the Vaucherias are 
brought forward in support of this theory. 
Ernst in 1907 published a preliminary note (6) on androgynous 
receptacles in Dumortiera velutina , Schiffn., and D. trichocephala , (Hook.) 
N. ab E., and in 1908 a very full and interesting paper ( 7 ), entitled ‘ Unter- 
suchungen iiber Entwicklung, Bau und Verteilung der Infloreszenzen von 
Dumortiera ’. Androgynous receptacles would seem to be very common in 
these species, and were found abundantly in specimens gathered from many 
different localities. The nature of the disturbance of the usual arrangement 
in these cases is very much more complicated than in the case of Preissia , 
the proportion of the female to the male portion varying within wide limits. 
As in Preissia , the antheridia are borne on the upper surface, and the whole 
of the branch is male. Pure male and female gametophores are very 
commonly found on thalli which bear androgynous receptacles. 
