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MISSOURI BOTANICAL GARDEN. 



These morphological features of Cassia may not be dis- 

 cussed here although they have figured conspicuously in 

 all the ecological discussions pertaining to these genera. 

 Their true significance has probably not yet been correctly 

 interpreted. 



On C. chamaecrista in Iowa Todd saw a small humble 

 bee. In Illinois Robertson observed four species of Bom- 

 bus collecting pollen. " Landing upon the anthers, they 

 seize them between their mandibles and stroke them down- 

 wards with a sort of milking motion." In a later paper 

 he states that the flowers are visited by the pollen collecting 

 female of the oligotropic Podalirius ivahhii. In eastern 

 Kansas, Harris and Kuchs observed one species each of 

 Apis, Agapostemon, Jfelissodes and Bombus. Near St. 



Louis I have observed Bombus. 



According to the observations made by Meehan, Robert- 

 son and myself, C '. Marylandica is visited by Bombus. 

 Pollen is collected only from the smaller upper stamens, 

 the three lower ones serving the insect only as a sup- 

 porting platform if at all. Flowers protected against 

 insect visits do not produce fruits. The pollen from the 

 large lower or the three smaller upper stamens, may effect 

 fertilization, but whether there is a difference in the effi- 

 ciency of that from the two kinds of stamens is not 

 known. 



In an unidentified species from Brazil related to C. 

 laevigata Fritz Miiller observed Bombus violaceus and 

 species of Centris collecting pollen from the short, central 

 anthers while the two long, lower anthers and similarly 

 shaped pistil are so much curved as to strike with the 

 anther tips and the stigma the dorsal surface of the 

 abdomen of the visiting insect. The large, lower stamens 

 are of the same color as the smaller, central ones and 

 were observed to be visited extensively by small insects 

 which despoiled them of their contents without effecting 

 pollination: Trigona elegantida y T. lilliput and a large 



