194 Trans. Acad. Set. of St. Louis. 



The description by Duual in the I^rodromus is similar to 

 that in the Botanical Register. Rose * says : "In the sterile 

 flowers the calyx is naked and the lower anthers much longer 

 (6 lines long); in the fertile and lower flowers the calyx is 

 armed with prickles and the anthers nearly even or often 

 longer." 



The only reference to the pollination of this plant known 

 to the writer is that of Delpino f who places in it his Seventh 

 Class under " Tipo Melastomaceo." " Solanum Amazoni- 

 cumX antere biporose all'apice. Stami superiori sterili, ab- 

 breviati e metamorfizzati in fulcri." 



In 8. Amazonium^ then, the structure of the calyx, corolla 

 and stamens has undergone a strong modification in the two 

 types of flowers. From what we know of the pollination of 

 S. rostratxim and of certain species in other families there 

 can be no reasonable doubt that S. Amazonium is pollinated 

 by insects. In this case, then, it ma}^ be that certain of the 

 secondary modifications in the polygamous flowers of this 

 species are real modifications for the securing of pollination, 

 but for a clear understanding of the structures direct ecolog- 

 ical observations are desirable. 



In the section Melongena there are found, according to 

 Dunal and Heckel, modifications in the inflorescence, in the 

 calyx and even in the stamens of the staminate and pistillate 

 flowers. In S. sisymbrifoliuvn a difference in the armature 

 of the calyx of the hermaphrodite and staminate flowers has 

 been recorded but it is not nearly so conspicuous in living 

 material as in 8. i}yracanthum where the difference is very 

 marked. In man}^ other armed species the same difference 

 will doubtless be found. 



According to Heckel there exists in the flowers of some 

 species of the section Melongena a real unisexual condition so 

 that the plants are monoecious. In his key Dunal divides 

 his section Polygamia into monoecious and dioecious forms. 



* Rose, J. N. List of Plants Collected by Dr. Edward Palmer in Western 

 Mexico and Arizona in 1890. (Cont. U. S. Nat. Herb. 1 : 91-127. 18910 



t Delpino, Federico. Ulteriori Osservazioai. Parte II. fasc. II. Milano. 

 1875. Estratto dagle Atti. Soc. Ital. Sci. Nat. in Milano, 1873-1874, 



X Evidently a typographical error, the name being S. Amazonium. 



