228 BENEDICT: NEW VARIETIES OF NEPHROLEPIS 
One of the interesting morphological possibilities is found in a 
problem under study, to determine whether new bud sports do 
not always appear first in the form of a variant leaf on the parent 
plant, this leaf showing the line of variation which the new form 
afterward fulfills. The solution of this problem depends on the 
possibility of determining whether each leaf has a subtending 
runner, and whether all the new plants from a given runner are 
alike and partake of the characteristics of the connected leaf. 
The problem, stated in other words, is to determine whether the 
actual process of variation takes place first in the cells of the leaf 
and is repeated in the runner and its sports, or whether the varia- 
tion may not take place in the runner itself. 
The fact that varieties in the division series do not always 
differ inter se merely by division, but also sometimes in the size 
and shape of the segments et al., and the further fact that other 
variations occur, such as dwarfing and ruffling, are in opposition to 
the conclusions reached by R. G. Leavitt,* who suggested that the 
appearance of varieties showing an increase in division was due 
. merely to a translocation of the ability to divide from the whole leaf 
to the pinnae, a phenomenon to which he applied Bateson’s term 
of homoeosis. To accept the hypothesis of such a translocation, 
it would be necessary to find that the twice-pinnate form differs 
from the once-pinnate form, from which it arose, merely in the 
amount of division, a supposition which is hardly supported by 
facts. 
A further argument for the hypothesis of homoeosis adduced by 
Leavitt, and applied not only to these ferns but also, for example, 
to the horse-chestnut, lay in the fact that the new forms possessed 
no utilitarian advantage over their parents. The fact that the 
horse-chestnut leaf cuts off each pinna by a distinct callus as well 
as its petiole base, and that this double decision appears to have 
no adaptive value, was advanced as confirmatory of the homoeosis 
thesis. This is interesting, but will hardly be accepted as an 
argument in view of modern objections to teleological explanations. 
It may be noted that Eimer, twenty and more years ago, made 
a most determined stand against the belief that adaptability was 
a prime necessity in the appearance of new characters and the 
evolution of new forms. 
* Bot. Gaz. 47: 30-68. Ja 1909. 
