BREEDING NEPHROLEPIS FERNS 
‘‘Fver-Sporting” Types and the Methods of Propagating and Disseminating 
Them—New Forms May Be Obtained from Spores of Nephrolepis 
Ferns—Suggestions for Practical Growers 
SARKIS BOSHNAKIAN 
College of Agriculture, Cornell University, Ithaca, N. Y. 
(of which the popular Boston 
fern is the best-known repre- 
sentative) can be divided in two 
groups, on the basis of their genetic 
behavior; first, those which show varia- 
tion only when propagated sexually, by 
spores; and second, those which produce 
new varieties asexually. 
The first group includes more than 
ninety species and varieties, all of which 
are either found growing wild in semi- 
tropical regions or have been produced 
from spores by breeders. Of these may 
be mentioned the widespread com- 
mercial varieties Nephrolepis exaltata, 
cordata compacta, plumosa, davallioides, 
canaliculata, and so on. 
The second, and more interesting, 
group is limited to the Boston fern, 
botanically known as Nephrolepis exal- 
tata bostoniensis, and all its sports, of 
which we have many. 
In a state of nature, ferns are often 
hybrid. The sexual organs are located 
in such a position as almost wholly to 
prevent self-fertilization. The spores, 
found in large numbers as_ kidney- 
shaped, brown, fruiting bodies on the 
under side of the leaflets, produce occa- 
sionally new forms when sown. So far 
as results show, the ferns of the first 
group breed true when propagated 
asexually, and in England a large num- 
ber of new varieties, such as concinia, 
and May: have been produced in this 
way from seedlings. 
The ferns of the second group, that is 
those derived from the asexual varia- 
tions of the Boston fern, may also be 
propagated from spores, despite the 
general belief that the spores are sterile. 
SERNS of the genus Nephrolepis 
I have raised a number of seedlings 
from the spores of the Boston fern and of 
some of its sports; those with finely 
divided leaves produce no fruiting 
bodies, but the others with uncrested 
leaflets yield spores in abundance. 
GERMINATION IS SLOW 
It is considerably harder to grow the 
ferns of the second group than those of 
the first, or of eother *genera- > ihe 
ferns of the first group with the excep- 
tion of a few, such as N. davallioides, 
N. d. furcans, and perhaps some others, 
germinate promptly at the end of a 
certain number of days. N. exaltata, 
for instance, takes twenty-six days to 
germinate, and N. plumosa twenty-four; 
all the spores germinate at almost the 
same time. Such is not the case, 
however, with the Boston ferns. Out 
of thousands of spores, only a few may 
germinate at the end of a month or 
more; the rest keep appearing, a few 
at a time, for many months afterward. 
They are very sensitive to the amount 
of moisture which surrounds them; and 
since nowhere, so far as I know, are 
directions given for germinating the 
spores of these plants, it may be useful 
for me to discuss the subject before 
proceeding to treat of the more usual, 
asexual method of propagation. 
In an experiment to determine the 
best medium in which to sow Boston 
fern spores, different materials, such 
as loam, sawdust, paper pulp, filter 
paper, asbestos, cinders, cotton and 
leaf mold were used. The comparative 
efficiency of different containers was 
also tested. The results showed that 
the best medium was well-decayed oak- 
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