THE DEHISCENCE OF ANTHERS BY APICAL TORES. 225 



apparently undescribed species, and by Centris lineo- 



latus. 



Trelease saw C. obtusifolia visited by Bombus in central 



Alab 



Schrottky observed Centris discolor regu 

 pollen on C. splendida at S. Paulo, Brazil, 

 saw species of Centris collecting the polle 



sularis. 



At Para, Ducke observed on C. Hoffman 



Here 



Df C 



species with very large flowers, Xylocopa, Centr 



E 



In Chile, Johow saw C. closiana visited by Bomb 



chilensis. 



Mimus with its head yellow 



pollen, from, as he thought, a Cassia. Delpino records 



Fries once 



Cassia (?) as visited by Nectai 

 observed C. bicapsularis visited for insects by Chloros- 

 tilbon auriventris. He found the species regularly visited 

 and pollinated by Bombus carbonarius. 



Our knowledge of forms other than Solanum and Cassia, 

 is, so far as direct observations are concerned, very frag- 

 mentary. Brown studied the flowers of Labichea Ian- 

 ceolata, and, finding the same right- and left-handed ar- 

 rangement as in 8. rosiratum, concluded that the method 

 of pollination is the same. It can hardly be doubted that 

 the other forms of the Cassieae are, at least for the most 

 part, dependent upon the larger pollen-collecting bees for 

 their fertilization. 



Mayacaceae and Rapateaceae no 



observations have been published. 



Of the floral ecology of the Commelinaceae under con- 

 sideration we are quite ignorant. I have been able to ex- 

 amine living material of one species of Dichorisandra and 

 to convince myself that there is no secretion of nectar. 

 The ecology of the flowers of some genera of the family is 

 quite well known, and comparative evidence makes it very 



15 



