FUNARIA HYGROMETRICA (l.) SCHREB. 389 
sexes occurring on an axis of Mnium hornum, a species which the Marchals 
(1907) had found to be strictly dioecious. Similar exceptional conditions 
had been reported in the same species and in Bryum caespiticium by the 
Marchals (1909); in Brachythecium erythrorhizon by Lindberg (1879); in 
Plagiothecium sylvaticum by Bergevin (1902); in Atrichum undulatum by 
Hy (1884); and in Mnium cuspidatum by Holferty (1904). Holding that 
these deviations from the normal sexual conditions can not be explained by 
the theory that the separation of sex is tied up with the reduction division, 
Wilson suggests that sex is determined by certain metabolic processes which 
are spread over a considerable number of cell generations and which, as a 
rule, are unaffected by external conditions. The observations of Philibert 
(1883) and Milde (1865) seem to support his views. The former reported 
small male plants arising by regeneration from the lower leaves of female 
plants of Homalothecium fallax, Camptothecium lutescens, and Fissidens 
decipiens, supposedly dioecious species; the latter author observed bud-like 
structures enclosing archegonia and antheridia on apparently sterile axes 
of Mnium cinclidioides , which has also been considered to be dioecious. 
Such unusual sexual conditions may be explained, according to Wilson's 
theory, by assuming the presence of some unusual factor which has inter- 
rupted the normal course of metabolism. 
In the non-dioecious mosses it is quite clear that the separation of sexual 
characters is not related to the reduction division, but takes place, if at all, 
at some later time in the life of the gametophyte. The Marchals (1909) 
suggest that in the species for which the denomination homothallic, borrowed 
from the terminology proposed by Blakeslee, would be more exact, the sexual 
differentiation appears only at the time of the formation of the sex organs. 
Strasburger (1910) holds that in monoecious and hermaphroditic 
mosses the separation of sex takes place at the time of the formation of the 
sex organs. According to Coulter and Coulter (1918, p. 189), the sexual 
characters are separated at a time later than that of the reduction division, 
in connection with some of the vegetative divisions of the bisexual gameto- 
phyte. As an example they cite Riccia in which the production of anther- 
idia only takes place for a considerable length of time, but is later succeeded 
by a period during which archegonia exclusively are formed. 
Concerning the sexual conditions in Funaria hygrometrica (L.) Schreb., 
the species especially considered in this paper, various conflicting statements 
have been made. It has been classed as dioecious by Sachs (1874, p. 368), 
Goebel (1882, p. 367; 1887, p. 174), Van Tieghem (1891, p. 982), Scott 
(1904, p. 132), and Bower and Gwynne-Vaughan (1905, pp. 211-212). 
Campbell (1895, P- 187; 1905, p. 195) says that "Funaria is strictly dioe- 
cious"; later, however (Campbell, 19 18, p. 622), this statement is corrected 
and reference is made to Boodle's results. 
Bruch, Schimper, and Giimbel (i 836-1 851, p. 298) described Funaria 
hygrometrica as having a primary stem terminated by a male inflorescence 
