320 - Cincinnati Society of Natural History. 
ON THE VARIABILITY OF THE ACORNS OF 
QUERCUS MACROCARPA, Michz. 
By Jos. F. JAmgEs, 
Custodian, Cincinnati Society of Natural History. 
It is a well known fact that all forms of life are subject to variation, 
but to what extent the variation is carried is a subject of much dis- 
cussion. The almost universally acknowledged belief now is, that all 
the species of any one genus are the descendants of a common ances- 
tor, and more remotely, the different genera of an order are likewise 
the modified descendants of a single form. Yet, nothwithstanding ~ 
this general belief, many are unwilling to admit that we see in the life 
about us, any tendency toward the formation of a new species. 
Now it is much to be doubted if such a thing as a species has any | 
existence in nature. The term is one which scientists have agreed to 
apply to an assemblage of individuals, which have certain character- 
istics in common ; but certain of these characteristics may be wanting 
in some individuals; and in a large number of individuals of one 
acknowledged species, we may and do find certain features changing, 
so that one species merges into another so imperceptibly that the line 
to be drawn between them is indistinguishable. This has come to be 
recognized to such an extent that many naturalists now hold that the | 
true method of classification is to group around certain centres, forms 
which have some thing in common. ‘To say that this or that form be- 
longs toa certain group of which some other form is the type. 
It is not the purpose here, however, to enter on a discussion of the 
meaning of the term species, nor of the limits of species, but to call 
attention to certain variations which have been noticed in a single 
species of plant, viz.: the Quercus macrocarpa, Michx., the Bur or Mossy 
Cup Oak. This tree, one of the finest of our Oaks, is remarkable for — 
the peculiar moss-like fringe which borders the cup of the acorn, and 
which ‘is present in no other species of Quercus of North America. 
The leaves of the tree are very variable, both in size and in outline. 
They are lobed, cut, pinnatifid and parted in such various degrees 
that it is hardly possible to find two of them alike; and leaves from 
the same tree would, if found in a fossil state, be ascribed to entirely 
different species. 
It is, however, to the acorns which I wish to call attention. Accord- 
ing to Michaux, these “are oval, and inclosed for two thirds of their 
