Chap. HI. EUBIACE^. 135 



styled flowers, after having been soaked in water, were rather 

 larger — ^in about the ratio of 100 to 91 — than those from the long- 

 styled flowers, and they were more triangular, with the angles 

 more prominent. As all the grains from the short-styled flowers 

 were thus characterised, and as they had been left in water for 

 three days, I am convinced that this difference in shape in the 

 two sets of grains cannot be aocountei for by unequal distension 

 with water. 



Besides the several Eubiaoeous genera already mentioned-, 

 Fritz Miiller informs methatt\vo or three species ofPsychotria 

 and Budge'i eriantha, natives of St. Catharina, in Brazil, are 

 heterostyled, as is Manettia hicolor. I may add that I formerly 

 fertilised with their own pollen several flowers on a plant of 

 this latter species in my hothouse, but they did not set a single 

 fruit. From Wight and Arnott's description, there seems to be 

 little doubt that Knoxia in India is heterostyled ; and Asa Gray 

 is convinced that this is the case with Diodia and Spermacoce 

 in the United States. Lastly, from Mr. W. W. Bailey's descrip- 

 tion,* it appears that the Mexican Bouvardia lelantha is hetero- 

 styled. 



Altogether we now know of 17 heterostyled genera 

 in the great family of the Kubiacese ; though more 

 information is necessary with respect to some of them, 

 more especially those mentioned in the last para- 

 graph, before we can feel absolutely safe. In the 

 ' Genera Plantarum,' by Bentham and Hooker, the 

 Eubiacese are divided into 25 tribes, containing 337 

 genera; and it deserves notice that the genera now 

 known to be heterostyled are not grouped in one or 

 two of these tribes, but are distributed in no less than 

 eight of them. Prom this fact we may infer that 

 most of the genera have acquired their heterostyled 

 structure independently of one another ; that is, they 

 have not inherited this structure from some one .or 

 even two or three progenitors in common. It further 



' Ball, of the Torrey Bot. Oluh,' 1876, p. 106. 



