1130 A TEXTBOOK OF THEORETICAL BOTANY 



term was introduced bv R. A. Salisbur^^ and used by de Candolle for a pecu- 

 liar concept, that of a zone of the receptacle called by the latter " the proper 

 receptacle ", which lies between the calyx and the ovary and forms the 

 common basis of the petals and stamens. He distinguished it from the 

 floral axis which bears the carpels and attributed its formation to the fusion 

 of abortive petals and stamens. It was depicted as sometimes extending 

 itself over the calyx to form the disc or cup of perigynous flowers, or as 

 rising round the ovary, with or without simuhaneous adhesion to the calyx; 

 in the former case leading to epigyny. Again torus and disc have often 

 been used synonymously but the disc is only one form of expanded torus 

 and to transfer the epithet " disc " to the torus zone in hypogynous flowers 

 is hardly justified. 



It is an interesting idea but not one for current use. At the present 

 day the term " receptacle " is applied to the whole floral axis from the 

 base of the calyx upwards and the torus is not regarded as a distinct organ 

 which, indeed, de Candolle did not claim that it was. 



Fig. 1 1 04. — Magnolia x soidajigeana. A three-branched recep- 

 tacle. 



Rare cases of branching of the receptacle are known, e.g., in Myosiirus 

 (Ranunculaceae) and Magnolia (Fig. 1104) which have unusually elongated 

 receptacles, but very little is known about the anatomy of such structures. 

 They are, of course, quite distinct from the appearance of branching which 

 may result from the partial coalescence of two flowers by the congenital 

 union of their rudiments. 



The interesting suggestion has been made by Burkill that the ten- 

 dency towards isomery in flowers is due to the action of hormones in deter- 

 mining the destination of primordia, these hormones coming from organs 

 whose nature is already determined and acting along lines of greatest 

 proximity, that is along the parastichies. 



This involves the view that an emergence on the receptacle is at first 



