2 0 ON THE FERII LIZ ATIOÎÎ
T h e ostiolar bracts formed a central boss on the same level as the male flowers, which
were arranged in three rows. The male flowers and their investing bracts were of almost
t h e same height. The perianth consisted of two outer overlapping loaves and of a
continuous closed hood investing the stamens the filaments of which were ver y short.
4. Diameter of araa occupied by ostiolar bracts in tbe cavity O'^S to 0''48
Breadth of zone of male floivers 0' 18
Breadth of peripheral fuiTCW of gall-floivers around zone of male flowors 0"18
T h e area occupied by the ostiolar bracts was flat, and was surrounded by a somewhat
elevated rim composed of the male flowers.
F r om the above data it is evident that in very many cases hardly any appreciable
changes occur in gall-receptacles to which insects do not gain entrance after the normal
period for access has been passed (Plate IV, fig. 23). A very slight general enlargement
m a y take place, and a certain increase in depth of the sti'atum of gall-fiowers, due to
elongation in the pedicels of some of the flowers. There is, however, comparatively little
increase in the size of the ovaries, and they therefore remain arranged in a single, or at
utmost in a double stratum. Due to the very slight increase in bulk of the gall-fiower
s t r a t u m , there is no need for any increase in the surface to which it is adapted, and tlje
i n t e r i o r of the rcceptacular wall remains smooth throughout. The cavity of the receptacle
remains empty, no fluid accumulating within it. In many cases the male flowers remain
p r a c t i c a l l y arrested at the stage of evolution which tlaey have attained at the normal period
f o r access of insects. In some cases, however, a certain amount of further evolution occurs,
t h e flowers increasing in height, and their swollen apices coming to project beyond their
i n v e s t i n g bracts. In certain instances the growth is so considerable as to cause the zone of
male flowers to form a prominent ridge around the central area occupied by the ostiolar
bracts, and at the same time to be curved outwards over the peripheral furrow of gallfiowers
so as almost entirely to conceal it f r om view.
II.—FEMALE RECEPTAOLES.
A.— Ckaraciers of female receptacles at the stage when they are ready fur the access of insects
{Plate I I I , fig. 2).
T h e following are the measurements of a specimen of average size : —
External diameter S'-O
Diameter of area of ostiolar bracts in the cavity 0*-o2
Breadth of peripheral area on ostiolar aspect of the cavity occupied
by flowers 0''3.5
Thickness of solid ostiolar plug
Tliickuess of receptaoular wall
Depth of floral stratum 0''-12
T h e area of ostiolar bracts formed a prominent mound on the centre of the ostiolar face
of the cavity. It was of yellowish-white colour and the rest of the surface of a bright rosemadder
tint, due to the continuous stratum of stigmata covering it. The ovaries were in
two tiers, due to the fact that some of the fiowers wei« sessile, while the others were shortly
pedicellate. In spite of this the stigmas foraied an almost even, uniform surface, part l y due
OF FICUS EOXBUUGHIL 21
t o absolute differences in the length of individual styles, partly due to those of the sessile
flowers following a more straight-lined course (Plate III, fig. 5).
B.—Characters nf ftmAe receptacles after ike access of insects and prior to complete maturation.
The following measurements were taken from a receptacle a few days after the entrance
of insects to its cavity
Diameter of urea of ostiolar bracts in the cavity 0" 77
Depth of ostiolar plug o"-52
Thickness of receptaoular wall 0''-34
Depth of stratum of flowers 0"-15
T h e ovaries were already visibly enlarged.
T h e first arid constant change which manifests itself is an increase in the thickness of the
s t r a t um of flowers, due to increased bulk, specially of the ovaries, and a consequent decreased
prominence of the mass of ostiolar bracts. In some cases the colour of the stigmatic surface
remains for long almost or quite unaltered, but in others the tint changes from pure rosemadder
to more or less brownish or brick-red. There is, however, never any tendency to
w i t h e r i n g or drying of the styles and stigmata, which, with the exception of the Dases of the
styles, remain persistent up to the period of full matm-ation and after the perianth has
dried up and the outer coats of the ovary and of great part of the axis of the flower have
undei'gone gelatinous degeneration. As in the case of gall-receptacles after the access of
insects, the increase in bulk of the ovaries is altogether out of proportion to that of the
surface from which the flowers arise, and space for them is obtained by their becoming
a r r a n g e d in superimposed strata, due to unequal growth of the pedicels. As, however, the
increase in bulk is not merely so great as is the case with the ovaries of the gall-flowers, the
number of strata is not so great, only four or five being present in many cases, and six or
seven in exceptional ones (Plate III, fig. 4). Another feature related to the minor
amplification of the ovaries in female receptacles is that the rcceptacular wall remains smooth,
throughout in place of acquiring increased surface by means of inequalities as that of
gall-flower receptacles does. Just as in the case of gall-flower receptacles, the cavity
becomes filled by fluid shortly after the access of the insects. The fluid differs from that
of the other receptacles in being clear, colourless, or at utmost pale yellowish, and watery with
only a few suspended particles, and in having an absolutely neutral reaction and a specific
g r a v i t y only of 1000.
C.—Characters of fully mature female receptacles to which insects have gained access
(Plate I I I , figs. 4, 6, 7).
The following are measm'ements taken from such a receptacle : —
External diameter 2°-3
Diameter of area of ostiolar bracts in the cavity 0'-i2
Thickness of reeeptacular wall 0"-24
Depth of stratum of flowers 0' - 30
This specimen was one of average size, and considerably larger ones occur. Their
dimensions, however, never approach those attained by the larger gall-receptacles, the