In some of these families the heterostyled condition 

 niiist have heen acquired at a very remote period. 

 Thus the three closely allied genera, Menyanthes, 

 Limnanthemum, and Villarsia, inhabit' respectively 

 Europe, India, and South America. Heterostyled spe- 

 cies of Hedyotis are found in the temperate regions 

 of North and the tropical regions of South America. 

 Trimorphic species of Oxalis live on both sides of 

 the Cordillera in South America and at the Cape of 

 Good Hope. In these and some other cases it is not 

 probable that each species acquired its heterostyled 

 structure independently ..of its close allies. If they 

 did not. do so, the three closely connected genera of 

 -the Menyantheae .aiiid the several, trimorphic species of 

 Oxalis must have inherited their structure ■ from a 



