VoL. 29 No. 8 
BULLETEN 
OF THE 
TORREY BOTANICAL CLUB 
AUGUST 1902 
The Origin of Asplenium ebenoides 
By MARGARET SLOSSON 
The question whether Asplenium ebenoides R. R. Scott is or is 
not a hybrid between Asplenium platyneuron (L.) Oakes and Camp- 
fosorus rhizophyllus (L.) Link has long been a vexed one. In 
Order to ascertain the truth by crossing A. platyneuron and C. 
rhizophyllus, 1 began experiments several years ago which had been 
Suggested by Mr. George E. Davenport.* Partial description of 
these experiments, together with a discussion of the advantages 
and disadvantages of various methods of attempting the hybrid- 
izing of ferns, has been announced already, + but it is necessary to 
refer here to the method that Mr. Davenport suggested and which, 
with slight modification, was at first adopted. . 
This method consists of dividing prothalli of two species be- 
tween the archegonial and antheridial regions before fertilization has 
taken place and planting the archegonial section of a prothallus of 
one of the species close to the antheridial section of a prothallus of 
the other, so that antheridia and archegonia come in contact. The 
idea is that should fertilization subsequently take place it can only be 
Cross-fertilization and the resultant plant a hybrid. It should be 
Said that although the formation of plants of pure species from 
asexual growth, which sometimes occurs on prothalli, would not 
be prevented, yet plants arising in this way can be distinguished, 
according to Dr. Farlow, from plants springing from fertilized 
archegonia and can, therefore, be detected and removed. 
On experimenting, however, two objections to this method 
were encountered: (1) Nearly all of the sections of prothalli 
* Papers Pres. Boston Meet. (1898), 9. 1899. 
t Fernwort Papers (ined. }. 
[Issued 30 August. ] 487 
