ASCLEPIADEAE 



95 



570. Stapelia L. 



Pinch-trap flowers with a carrion odour, which attracts flies fond of putrefying 

 substances. These effect cross-pollination by means of their proboscis. Kuhn 

 observed cleistogamy. 



1881. S. hirsuta L., and 1882. S. grandiflora Mass. Both these species are 

 native to the Cape. 



Visitors. Delpino noticed two Muscids (Sarcophaga carnariaZ., and Calliphora 

 vomitoria Z.) as pollinators. 



571. Gomphocarpus R.Br. 



Flower mechanism similar to that of Stapelia. The clips attach themselves 

 to the claws of hymeno- 

 pterous visitors. (Delpino, 

 ' Sugli appar. d. fecondaz. 

 nelle piante autocarp.,' pp. 

 3-14 ; Hildebrand, Bot. Ztg., 

 Leipzig, XXV, 1867, pp. 

 266-9.) 



572. Araujia Brot. 



Fig. 357. Asclepias curassavica, L. (after Herm. Mttller). 1 1 clips 

 1883. A. Sericifera (-J) and 8 polHnia (j/) attached to a butterfly's foot. 



Brot. (=A. albens G. Don, 



and Physianthus albens Mart). (Delpino, op. cit. ; Hildebrand, op. cit. ; A. Rogen- 

 hofer, SitzBer. ZoolBot. Ges., Wien, xl, 1890, pp. 67-8.) In this species the 

 poUinators are humble-bees, and the clips attach themselves to the proboscis. 

 A. Rogenhofer saw a moth (Plusia gamma Z.) hanging dead from the flower, while 

 strong humble-bees cannot be held fast, but tear away the clips. 

 Visitors. Vide supra. 



573. Boucerosia Wight et Am. 

 Delpino (op. cit.) states that the flower mechanism resembles that of Araujia. 



574. Hoya R.Br. 



Delpino (op. cit.) states that the clips become attached to the legs of visitors. 



1884. H. camosa R. Br. (Delpino, ' Sugli appar. d. fecondaz. nelle piante 

 autocarp.,' p. 9; Darwin, 'Forms of Flowers,' p. 331.) Delpino saw numerous bees 

 visit this species at Florence, drawing out the pollinia upon their claws. From one 

 plant which was carefully examined four-fifths of the pollinia had been removed 

 from their loculi, and some with germinating pollen-grains were found upon the 

 stigmas. This plant, however, and some from other ItaUan gardens, remained 

 completely sterile. Delpino suggests as a reason that all the stocks had been 

 vegetatively propagated from one and the same original plant. 



