:<> 



THE FERTILIZATION 



The ctiolar bracts formed a central boss on the same evel as the male flowers, which 

 * ;„,;,,;,, m thlV( . _,. The mal, flcwe* and their investing bracte were of almost 

 the. a" hefcht. The perianth consisted of two outer overlapping leaves and of a 

 ««il„« did hood investing the stamens the filaments of wlueh were very short. 



4 Diameter of area occupied by ostiolar bracts in the cavity 



Breadth of zone of male flowers 



0*42 to 0*-48 

 0*18 



0"18 



Th. 



Breadth of peripheral furrow of gall-flowers around zone of male flowers 



occupied by the ostiolar bracts was flat, and was surrounded by a somewhat 



elevated rim composed of the male flowers. 



From the above data it is evident that in very many cases hardly any appreciable 

 chants OOCUT in gall receptacles to which insects do not gain entrance after the normal 

 period ** access has been passed (Plate IV, fig. 23). A very slight general enlargement 

 may take place, and a certain increase in depth of the stratum of gall-flowers, due to 

 lomntion in the pedicels of some of the flowers. There is, however, comparatively little 





the size of the ovaries, and they therefore remain arranged in a single, or at 

 ut u<* in a double stratum. Due to the very slight increase in bulk of the gall-flower 



stratum, there is no need for any increase in the surface to which it is adapted, and th 

 intrrio; .»f the receptacular wall remains smooth throughout. The cavity of the receptacle 

 r. n tins empty, no fluid accumulating within it. In many cases the male flowers remain 

 pnu ti« ally arrested at the stage of evolution which they have attained at the normal period 

 for access of inserts. In some cases, however, a certain amount of further evolution occurs, 

 the flow rs increasing in height, and their swollen apices coming to project beyond their 



investing bracts. In certain instances the growth is so considerable as to cause the zone of 

 male Mowers to form a prominent ridge around the central area occupied by the ostiolar 



bracti, ;tn<l at the same time to be curved outwards over the peripheral furrow of gall 

 flowers so as imost entirely to conceal it from view. 



II. — Female Receptacles. 



A, — Characters of female receptacles at the stage when they are ready for the access of insects 



{Plate III, fig. 2). 



The following are the measurements of a specimen of 



External diameter 2"*0 



Diameter of area of ostiolar bracts in the cavity 0*'52 



Breadth of peripheral area on ostiolar aspect of the cavity occupied 



by flowers 0"'35 



Thickness of solid ostiolar plug ........ 0"*43 



Thickness of receptacular wall % 0"*24 



Dei'th of floral stratum , //, 12 





The area of ostiolar bracts formed a prominent mound on the centre of the ostiolar face 

 .f the cavity. It was of yellowish-white colour and the rest of the surface of a bright rose- 

 madder tint, due to the continuous stratum of stigmata covering it. The ovaries were in 

 two tiers, due to the fact that some of the flowers *eie sessile, while the others were shortly 

 pedicellate. In spite of this the stigmas formed an almost even, uniform surface, partly due 





