206 MORPHOLOGY OF ANGIOSPERMS 



ber of species but also of families. The tropical families repre- 

 sented in both hemispheres are Butomaeeae, Triuridaceae, 

 Palmaceae, Araceae, Eriocaulaceae, Commelinaceae, Amaryl- 

 lidaceae, Taccaceae, Dioscoreaceae, Burmanniaceae, and Orchi- 

 daceae. Those peculiar to the oriental tropics are Pandanaceae, 

 Aponogetonaeeae, Musaceae, and Zingiberaceae. Those peculiar 

 to the occidental tropics are Cyclanthaceae, Mayacaceae, Xyri- 

 daceae, Bromeliaceae, Haemodoraceae, Yelloziaceae, Canna- 

 ceae, and Marantaceae. 



8. The great preponderance of epiphytic forms in the 

 American tropics is probably associated with the culmination 

 of the rainy forest. The two great epiphytic families are 

 Bromeliaceae and Orchidaceae, the former being restricted to 

 the occidental tropics, and the latter much more abundant there 

 than in the oriental tropics. 



9. The peculiar distribution of the three genera of Stemona- 

 ceae is noteworthy and suggestive. Stemona. with four or five 

 species, ranges from the Himalayas to southern Australia. 

 Croomia has one of its species (C. pauciflora) in Florida, Geor- 

 gia, and Japan; while the other (('. japonica) is restricted to 

 Japan. The monotypic Stichneuron is restricted to the East 

 Indies. The occurrence of a single species of this oriental 

 family in Georgia and Florida, and that species native also to 

 Japan, is difficult to explain. 



ARCIIICHLAMYDEAE 



It is impossible to consider the geographic distribution of 

 the Archichlamydeae in such detail as that of the ALonocotyle- 

 dons. The series are so numerous and indefinite that a presen- 

 tation of their separate distribution would be confusing and 

 not very significant. An examination of available but very 

 insufficient data has resulted in the following extremely general 

 statements : 



1. Xo family has developed a world-wide distribution as 

 have several families of the Monocotyledons and Sympetalae. 

 It must be understood that this fact is related to the great 

 diversities in the group, that have resulted in the recognition 

 of numerous families. The family differences recognized by 

 taxonomists are perhaps not to be pressed too far in any com- 

 parison of the geographic distribution of the three great Angio- 



