I^'TRODUCTION•.
is papillose, varies in shap3, boing oyKiidrie, clavale, capitate, peltate, or infandibuliform •
and a few cases it is flat. In many species it is obliqnely truncate, and in not a few
bicrnral. It is, however, often very diffienlt to determine the exact form of the sti,.ma
from the fact that at an early stage the stigmas of all the fertile female flowers of" thè
same reeeptaele are joined together in a dense felted mass, from which it is nearly
impossible to detach any individual in a state of entirety. After fertilisation the ovary
becomes developed into an aehene, which tends to be rmilaterally emarginate (many
aehenes are very distinctly reniform), and the style becomes more lateral, or even
basal. The ripe achene has a ornstaoeons pericarp of a pale yellow colour and with
a more or less minutely tabercnlate or nndnlate surface. External to the crustaeeous
coat there is occasionally a glairy or viseid layer. The pericarp is never very thick
and sometimes it is eonspieuously thin. On ontting the achene open, the embryo is seej
with a small amount of albumen. I have not, however, paid much attention to the
relation of the albumen to the embryo. Not a few of the perfect female flowers fail to
be fertilised. But the fact of the barrenness of such is not recognisable until the achene
has been cut open and they are found to contain no embryo. E,xternally these infertile
aehenes exactly resemble those containing embryos.
Besides the above four kinds of flowers, there occur in all the species of Mens
which I have examined a set of iiowers whieh, adopting the name given to them by
Count Solms-Laubach, I call gall flowers. Jly own name for these was originally
imeei-titachi fimales ; but Count Solms-Laubach's name being much shorter and more
suitable, I have adopted it. The existence of these gall flowers in this genus as a
separate and distinct kind of flower, was first made publicly known by the distinguished
botanist just mentioned in B .UnitsU Zdlmg, Kos. 3-3 to 36 for ISSo. lly own" observations
and inquiries on Ficm have been in progress since 1878, but on account of
my miwillingness to publish aiiytldng until I had completed my rcscarch, I have been
anticipated in the publication of the facts about gall flowers. The gall flowers in many
respects resemble the fertile female flowers : they have in most eases a similar per-ianth,
an ovary, and a stjde. When fully developed, they are recognised at a glance by their
contairring the pupa of an insect, which can often be seen through the pericarp of the
false achene into which the ovary develops. But whether the pupa be visible or not,
or whether it be present or not, the false achene of the gall flower may in its later
stages be distinguished from the true achene of the fertilised ovary of the perfect or
fertile female flower by being more often pedicillate, and by its shape being usually
globular and rarely elliptic or reniform; by its smface being smooth, not minutely
tnbcreular or undulate and never viscid or glairy; and frequently also by the tense,
distended appear-ance of its tough membranous wall (false poricarp). The stylo is, as a
rule, much shorter and straighter than the style of the fertile female flower, and more
terminal, and it has very frequently a dilated tubular apex wliich occupies the situation
INTEODUCriO:i. vii
of the true stigma, but has often little or none of the viscid parenchyma characteristic
of that organ. These peculiarities in the nature of the stigma and the shortness of the
style are apparent in the gall flowers of many species from a very early stage. They
are not consequences of the deposit of the egg of an insect in the ovary, but, as Count
Solms-Laubach points out {Brii. Zdknuj, I.e.), such original peculiarities in the stylo and
stigma of the gall flower may rather dcter-mine the selection of it by the insect as the
nidus for its egg. There are, however, marry species of Ficus (more especially in
the gr-oup VrDs^ma) in which the gall and fertile female flowers are not charaeterised by
any marked differences in the form of style and stigma, and it is only by cutting the
ovaries open that the two can be distinguished.
Now there is probably notlring in itself very remarkable in the mere occuiTence in
the genus of mrmerous flowers having the general form of females, which yet, by reason
of certain peculiarities in their structure, are incapable of fertilisation by pollen and are
practically barren, while at the same time their very structural defects fit them for
becoming the nidus for the eggs of special insects. But when the manner in which
these malformed female flowers are disposed in the rcccptacles is inquired into, it
becomes clear that, through the interposition of insects, these malformed females may play
a most important part in the life-history of many species of the genus. In all the species,
except those included in the section Uroitii/im, the gall flowers occupy the same receptacles
as the males, while the fertile female flowers occu2)y different receptacles. In
other words, the majority of the species have two distinct sets of receptacles—one set
containing male and gall flowers, but no fertile female flowers; and another set containing
only fertile female flowers without any trace of either male or gall flowers. The
proportion of males to gall flowers in receptacles of the for-mer kind varies. In all
(excepting the Urosiiymas just mentioned) it is the rule to find the males confined to a
zone of gi-eater or less wudth at the apex of the reeeptaele just mrdcr the scales which
close its mouth. Sometimes tliis aone is very iiarTow indeed, and consists of only a
single row of male flowers, and that row not always a comialete one; the remaining part
of the interior of the receptacle being occupied by gall flowers. In by far the majority
of eases these two kinds of receptacles, so physiologically distinct, are nndistinguishable
by external characters, and they ai-e both borne by the same individual plant. They
look exactly alike until one cuts them open and examines their contents. The most
notorious of the few exceptions to tliis rule is the common eatable fig {Ficm Carici), in
which spccies the male and gall flowers occuiiy elongated receptacles borne in one set of
individual trees, while the fertile female flowers occupy more or less globular receptacles
which are borne by a difEerent set of trees. So different in appearance are the two
kinds of receptacles hr F. Crtma, that the trees bearing them (although they have sbnilar
leaves) have almost from time immemorial been considered distinct species, known by
distinct names—the former being called the Caprrfig, the latter the Fig. A vague idea of