Fagaceae , and its Bearing on the Affinities of the Group. 521 
d.b. 
st. 
through the association of originally independent male and female flowers 
within a common perianth. 
In Castanea the structure of the flower is the same as in Castanopsis , 
and, apart from the greater number of main bundles in the ovary wall, it is 
the same in Fagus. 
In Quercus the presence of groups of stone cells in the outer layers of 
the receptacular wall makes it 
almost impossible to cut thin 
serial sections of the ovary at the 
later stages when the bundles 
are fully lignified, but such sec- 
tions as were obtained showed 
the presence of carpellary bun- 
dles below the loculi, breaking 
up into dorsal branches and 
placental strands just as in Cas- 
tanopsis. The dorsal branches, 
however, frequently run inde- 
pendently up to the styles, so 
that the ovary wall often shows 
twenty or more bundles. 
So far, in the examination 
of the flower, a trimerous struc- 
ture is apparent throughout ; it 
is only in the pedicel that we 
come across any indication that 
this trimery is adaptive, the re- 
sult of the development of the 
flowers within a confined space. 
In Fagus the whole vascular 
supply of the flower springs from 
fifteen bundles arranged in three 
groups of five ; in Castanopsis 
the same three groups of five 
main bundles may be traced, and 
Fig. 8. Diagram of course of bundles in flower 
of Castanopsis chrysophylla. m.b main bundles ; 
per. t branch to perianth ; st., branch to stamen ; d.b., 
branch to style; c.b., carpellary bundle ; p.b ., placental 
branches ; i.b., branches in the outer integument of ovule. 
frequently a fourth group is present, corresponding to a fourth loculus in the 
ovary, which, if fully developed, would bring the number of main bundles 
up to twenty. These fifteen to twenty bundles combine in various ways to 
give the twelve which traverse the ovary wall. 
In Castanea , on the other hand, the middle flower of the dichasium, 
which is compressed on both sides, sometimes shows only two groups of 
five main bundles, the third group being altogether missing. 
It seems not improbable, therefore, that the organs of the flower were 
