194 FAMILIES OF FLOWERING PLANTS 



like seeds. The Brazil-nut is a familiar example ; its fruit, partly sec- 

 tioned, is shown in Figure 171. 



Fig. 171. Fruit and seeds of the Brazil Nut {Bertholletia excelsa) greatly reduced. 



Family Rhizophoraceae. Mangrove Family. This interesting 

 group consists of about 14 genera and 50 species, shrubs or trees, some 

 of which are not strictly maritime like the true mangroves. The great 

 interest attaching to the latter lies in the fact that the seeds germinate 

 while the fruit remains attached to the parent plant and the radicle pro- 

 jects downward like a plummet, ready to secure prompt attachment in 

 the loose mud upon which it finally falls. The flowers have both calyx 

 and corolla, each of 4 parts, the stamens as many or twice as many. 

 The capsular fruit contains one or few seeds.* The mangroves proper 

 belongs to the genus Rhizopliora, but several related genera have the 

 same habit. The family is distributed through the tropics of both 

 hemispheres. 



Family Combretaceae. Myrobalan Family. Contains about 23 



Fig. 172. White buttonwood {Conocarpus erecta). 



*See article by the author in the present number of this journal, on " Plant 

 Agencies in the Formation of the Florida Keys, ' ' for an account of the mangrove. 



