266 MORPHOLOGY OF AKGIOSPERMS 



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

 sented in both hemispheres are Butomaceae, Triuridaceae, 

 Palmaceae, Araceae, Eriocaulaceae, Commelinaceae, Amaryl- 

 lidaceae, Taccaceae, Dioscoreaceae, Burmarmiaceae, and Orchi- 

 daceae. Those peculiar to the oriental tropics are Pandanaceae, 

 Aponogetonaceae, Musaceae, and Zingiberaceae. Those peculiar 

 to the occidental tropics are Cyclanthaceae, Mayacaceae, Xyri- 

 daceae, Bromeliaceae, llaemodoraceae, Velloziaceae, Canna- 

 ceae, and Marantaceae. 



8. The great preponderance of epiphytic forms in tin.' 

 American tropics is probably associated with the culmination 

 of the rainy forest. The two great epiphytic families are 

 Bromeliaceae and Orehidaceae, 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 (C. 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. 



AiiCIIIClILAMYDEAE 



It is impossible to consider the geographic distribution of 

 the Archichlamydeae in such detail as that of the Monocotyle- 

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

 tation of their separate distribution would lie confusing and 

 not very significant. An examination of available but very 

 insufficient data has resulted in the following extremely general 

 statements : 



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

 have several families of the Monocotyledons and Sympetalae. 



It must be underst 1 that this fact is related to the great 



diversities in the group, thai have resulted in the recognition 

 of numerous families. The family differences recognized by 

 taxononiists are perhaps not to he pressed too far in any com- 

 parison of the geographic distribution of the three great Angio- 



