IV 



INTRODUCTION. 



cles or ampbantha. They vary in colour, form, size, and in the situation which 



they occupy on the plant. In some species of the section Urostigma the receptacles 

 while young are enclosed in calyptriform involucres, which are thrown off at an early 

 stage of the expansion of the receptacles. These hoodlike bodies persist longer in 

 F. altissima than in any other species, but on the whole they are too fugacious to found 

 specific characters upon. The hollow receptacle has walls of more or less fleshy texture, 

 and its mouth is occupied by rows of bracts, which in the majority of cases so interlock 

 as practically to close it. The lower of these bracts often bend downwards into the cavity 

 of the receptacle, curving round the upper flowers; the middle bracts are more or less 

 horizontal in direction ; while those towards the upper or outer part of the mouth project 

 therefrom, so as to be visible externally and to form a more or less prominent apical 

 umbilicus. In a few species the mouth is surrounded externally by a more or less clearly 

 defined annul us, formed of coalesced bracts. In shape the receptacle varies from spher- 





oidal to ovoid, ellipsoid, obovoid, or pyriform. In most species involucral bracts are 

 found at the base of it. These bracts (which are alluded to in the following pages as 

 the basal bracts) are usually three in number. They are generally distinct from each 

 other, but sometimes they are slightly united, so as to form a kind of involucral cup. 

 The receptacle in many species is contracted towards its base, and in some this contrac- 

 tion is carried to .such an extent that a kind of false stalk is formed. This stalk-like 

 contraction must not however be confounded with the peduncle proper, by which, in 

 many species, the receptacle is attached to the axis; and as a fact the stalk may 

 invariably be distinguished from the peduncle proper by the position of the involucres 

 just referred to, which are attached at the apex of the peduncle proper, but at the 

 base of the pseudo-stalk. As regards situation, receptacles may occur in pairs in the 

 axils of the leaves (e.g. Urostigma), or they may be solitary in the same situation from 

 the abortion of one of the original pair (e.g. Syncecia). They may also occur in axillary 

 fascicles of three or more. In a large number of species (e.g. Neomorphe) the receptacles 

 are borne on tubercles (i.e. shortened leafless branchlets) from the larger branches or 





from the stem ; while in one set of species ( Covellia) the receptacles are borne on Ion 

 sub-aphyllous branches, which, proceeding from the stem near its base, either trail 



X, 



along the surface of the ground or bury themselves in the soil. In one very remarkable 

 species ( F. Mimhauae) the receptacles are collected in dense capitula, which in turn are 

 arranged in long leafless branches which droop towards, but hardly reach, the ground. 

 In a few species (e.g. F. hupida) receptacles occur both in the axils of the leaves and on 

 stem tubercles. In size, as in colour, the receptacle varies much, and e> 

 specific characters are derived from these differences. 



The flowers, which are mostly unisexual, are situated on the inner walls of the recep- 



parated from 



appendages 



cellent 



tacle. They may be either sessile or peuicillate. In some species they 



each other by scales or bracteoles, and in others by hairs, both of which 



