Vol. 50 No. 3 
BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
MARCH, 1923 
Polyembryony developed under experimental conditions 
in certain polypodiaceous ferns 
AusTIN ETTER 
(WITH PLATE 4 AND SEVEN TEXT FIGURES) 
Among liverworts and in many mosses, polyembryony, or 
the development of two or more sporophytes upon a single 
gametophyte, is the rule rather than the exception. Among the 
Pteridophytes, however, the phenomenon is of less frequent 
occurrence. 
While experimenting with prothallia by lighting them both 
above and below, Heinricher secured two perfect embryos on 
one prothallium, one above and one below. The value of this 
as an example of polyembryony was questioned by Atkinson 
(’93) in that it might be considered an abnormal case. 
As stated by Atkinson (’93), ‘‘Rauwenhoff (’89) notes the 
development of two embryos on single prothallia of Gleichenia. 
In both of these cases, however, we are not informed of the com- 
parative strength or advanced condition of growth of the em- 
bryos, so that it may be an open question whether both of the 
embryos on a single prothallium could have developed into in- 
dependent plants.” In at least one other instance, however, 
Rauwenhoff (’91) described and figured, according to Buchholz 
('22, p. 263), polyembryony in Gleichenia, indicating the relative 
size and condition of the two embryos. 
During his study of Osmunda, Campbell (’92) observed two 
embryos on one prothallium, one of which was much smaller 
{THe BuLvetin for February (50: 60-94. pl. 2, 3) was issued February 23, 
1923.] 
95 
