202 THE AMERICAN NATURALIST. [Vor. XXXV. 
has been maintained, and are the result of extensive degenera- 
tion, then these colors may be the relics of an earlier higher 
stage. But if the perianth has always remained rudimentary, 
and the form of the inflorescence has been developed in con- 
nection with wind-fertilization, then the coloring is due largely 
to chemical and physical conditions. It is desirable to con- 
sider briefly the origin of the ament, for which the Fagaceze 
present special advantages. The ament, though frequently 
referred to as a spike, is in reality a contracted panicle. It is 
composed of clusters of flowers with a common involucre 
arranged around a central axis or rachis, and is, consequently, 
a branch system with the lateral axes of the first and second 
order, which would bear solitary flowers, aborted or eliminated. 
In the oak the female flower still remains solitary, and with 
the involucre of many bracts represents a non-developed 
branch; further steps are presented by the beech with two 
flowers, and the chestnut with several in an involucre. The 
association of these clusters along a common rachis would pro- 
duce an ament, the production of which is the result of con- 
traction and concentration, of elimination of axes, and arrested 
development. There is no evidence that the perianth was ever 
large and well developed. The primitive flowers were probably 
perfect and possessed a simple and undifferentiated perianth, 
which in certain genera has been wholly or in part replaced by 
bracts orscales. The Piperales are regularly perfect, and rudi- 
mentary ovaries and stamens are of frequent occurrence in the 
Amentacez, especially in the Fagacec. The causes which 
have led to the separation of the sexes are still involved in 
much obscurity, though it is well known that nutrition and 
climate influence differently the stamens and pistils. It is 
evident, however, as Darwin has remarked, that cross-fertiliza- 
tion must have been assured before the flowers became declinic, 
since otherwise the species would have perished. When the 
antiquity of these families, their wide geographical distribution, 
the vast number of individuals,— in the case of the birch form- 
ing vast forests in Russia, — as well as their floral structure, are 
considered, there seems no reason to suppose that the flowers 
were ever entomophilous and conspicuous. 
