230 



BIOCHEMICAL SYSTEMATICS 



C. aphylla and C. crossiramea. According to Gilg and Heinemann 

 these two species are placed in Bentham's series Aphylla on a super- 

 ficial character (namely, absence of leaves). Gilg and Heinemann 

 treated C. aphylla as a leafless member of the series Pachycarpae, 

 while C. crassiamea was placed in a newly proposed series, Crassiraea. 

 Although these authors based their conclusions, in part, on certain 

 morphological and geographical evidence, considerable weight was 

 apparently given to the fact that C. aphylla tested positively for 

 emodin (as did the fourteen other species tested in the series Pachy- 

 carpae) while C. crassiramea was negative. A similar observation was 

 perhaps also responsible for the author's establishment of the series 

 Aculeatae, its only species, C. aculeatae, which was negative for 

 emodin, having previously been placed in the series Pictae (Bentham, 

 1871); the latter testing positive for those nine species examined. 



However, Hegnauer (1959) has summarized more recent 

 literature on the anthraquinones of Cassia, and has noted reports 

 of a much broader distribution of anthraquinone in the genus. For 

 example, several species of the sub-genus Fistula have been reported 

 to contain anthraquinones: C. fistula, C. leptophylla, C. carnaval, and 

 C javanica. The majority of sections in the sub-genus Senna now 

 are known to have at least one representative which produces anthra- 

 quinones, and within the section Chamaesenna, two series other than 

 those noted by Gilg and Heinemann are included among anthra- 

 quinone producers. Finally, C. mimosoides, of the sub-genus Lasio- 

 rhegma (section Chamaecrista) has been found to produce anthra- 

 quinones. The situation in Cassia is, then, similar to that in Rhamnus. 

 It is quite hkely that an intensive study of the distribution of 

 quinones in the large genus Cassia would disclose a pattern. Such a 

 study would have to include a characterization of the more common 

 quinones as well as analysis of various plant organs, for it has been 

 demonstrated that related species may differ radically in the distribu- 

 tion of quinones within the plant. 



