RARE TROPICAL TREES OF SOUTH FLORIDA 



By Elbert L Little, Jr. 1 



INTRODUCTION 



South Florida has the greatest collection of rare 

 native trees anywhere in continental United States, 

 about 100 tropical species found nowhere else in the 

 country. An inventory may be timely, because of the 

 increasing interest in preservation of endangered 

 species. This compilation of about 60 species of rare 

 tropical trees of the 3 southernmost counties (Dade, 

 Monroe, and Collier) or slightly beyond summarizes 

 their distribution and shows their occurrence within 

 parks and other preserves. All are native also in the 

 West Indies and would be classed in Florida as bor- 

 der or peripheral species. 



According to this compilation, a few of the rarest 

 tree species merit additional protection in new pre- 

 serves. All the native palms and a few other tree 

 species of South Florida are protected by State law. 



The second in a series on rare and local native 

 trees of the United States, this report revises a 

 preliminary one prepared in 1971. The first was 

 "Rare and Local Conifers of the United States" (Lit- 

 tle 1975 2 ). 



The Endangered Species Act of 1973 (Public Law 

 93-205) stressed the need for an inventory and au- 

 thorized the Smithsonian Institution to prepare 

 within 1 year a proposed list of endangered and 

 threatened plant species. This report (Smithsonian 

 Institution 1975) contains more than 2,000 species. 

 The author submitted names of rare tree species, 

 based upon Forest Service records and publications 

 (Little 1953, 1971). 



The Act also provides that the Secretary of the 

 U.S. Department of the Interior must review this 

 report and determine whether or not any species is 

 truly threatened or endangered. Three lists derived 

 from the Smithsonian report were published in the 

 Federal Register (U.S. Department of the Interior 

 1975) as notice of consideration. However, only pro- 

 posed lists are available, and there is no official, 

 approved list of threatened or endangered plant 

 species. 



'Chief dendrologist, Forest Service, U.S. Department of Ag- 

 riculture, Washington, D.C. 20250. 



2 Names and dates in parentheses refer to Literature Cited, p. 

 18. 



South Florida, roughly the lower third of the 

 State south of Lake Okeechobee, has a subtropical 

 climate. It is in plant hardiness zone 10, which has 

 average annual minimum temperatures of 30° to 40° 

 F. The Florida Keys extend nearly 150 miles south- 

 westward. This island chain is the only part of the 

 State that never has freezing temperatures and 

 which has a truly tropical climate. 



The Florida Keys and southern part of the main- 

 land possess many kinds of wild tropical trees that 

 are not hardy in cool climates and that cannot sur- 

 vive winters northward. Obviously, some species 

 are rare. Nearly all are found in greater numbers 

 through various islands of the West Indies or even 

 beyond. 



The rare tropical trees of South Florida are not 

 classed as endangered or threatened with extinction 

 in a technical sense under the Endangered Species 

 Act and are not on the proposed list by the Smithso- 

 nian Institution cited above. They are excluded be- 

 cause of additional occurrence outside the United 

 States. 



Nevertheless, the rare tropical trees of South 

 Florida merit inclusion in the State list of rare 

 plants. The list is important nationally because these 

 tropical species are native in no other State. Disap- 

 pearance in Florida, though not extinction of a 

 species, would make the wild plants unavailable in 

 this country. 



Definitions 



Two definitions may be quoted from the En- 

 dangered Species Act. "The term 'endangered 

 species' means any species which is in danger of 

 extinction throughout all or a significant portion of 

 its range . . . ." "The term 'threatened species' 

 means any species which is likely to become an en- 

 dangered species within the foreseeable future 

 throughout all or a significant portion of its range." 

 Survival of an endangered species requires assist- 

 ance. When a species has small numbers of individu- 

 als, loss of or changes in habitat, over-exploitation, 



