330 CLEISTOGAMIC FLOWERS. CHAP. VIII. 



fertile stamen; the style is almost obsolete, with the 

 three stigmatic surfaces directed to one side. Both the 

 perfect and cleistogamic flowers produce seeds.* 



The cleistogamic flowers on some of the Mal- 

 pighiaceae seem to be more profoundly modified than 

 those in any of the foregoing genera. According to 

 A. de Jussieu f they are differently situated from the 

 perfect flowers; they contain only a single stamen, in- 

 stead of 5 or 6; and it is a strange fact that this 

 particular stamen is not developed in the perfect 

 flowers of the same species. The style is absent or 

 rudimentary; and there are only two ovaries instead 

 of three. Thus these degraded flowers, as Jussieu 

 remarks, " laugh at our classifications, for the greater 

 number of the characters proper to the species, to the 

 genus, to the family, to the class disappear." The 

 calyces of the perfect flowers are studded with glands, 

 and their absence on the cleistogamic flowers may prob- 

 ably be explained by an observation of Fritz Miiller, 

 who informs me that in the one species, Bunchosia 

 Oaudichaudiana, the fertilisation of which he has often 

 witnessed, the perfect flowers are regularly visited by 

 bees belonging to the genera Tetrapedia and Epicharis. 

 These bees sit down on the flowers, gnawing the 

 glands on the outside of the calyx, and in doing 

 so the under sides of their bodies are dusted with 

 pollen, by which afterwards other flowers are ferti- 

 lised. Such visits to the cleistogamic flowers would be 

 useless. 



As the Asclepiadous genus Stapelia is said to pro- 

 duce cleistogamic flowers, the following case may be 

 worth giving. I have never heard of the perfect flowers 

 of Hoya carnosa setting seeds in this country, but some 



* Dr. Kirk, 'Jour. Linn. Soc.,' f 'Archives dn Museum.' trim. 

 vol. viii. 1864, p. 147. iii. 1843, pp. 35-38, 82-86, 589, 598. 



