oaks and sand pine has been mentioned. Two en- 

 demic tree species there are: Caryafloridana Sarg. , 

 scrub hickory, and Illicium parviflorum Michx., 

 yellow anise-tree. Two endemic tree varieties there, 

 both originally named as species, are: Ilex opaca 

 var. arenicola (Ashe) Ashe, dune holly, and Persea 

 borbonia var. humilis (Nash) Kopp, silkbay. 



Likewise, northern Florida has 4 endemic tree 

 species: Taxus floridana Nutt., Florida yew; Tor- 

 reya taxifolia Arm, Florida torreya; Magnolia 

 ashei Weatherby, Ashe magnolia; and Salix 

 floridana Chapm., Florida willow (also in 2 counties 

 of Georgia). 



Sand pine, Pinus clausa (Chapm.) Vasey, merits 

 mention as a common tree species widespread across 

 Florida but restricted to that State and Baldwin 

 County, Alabama. It ranges into South Florida 

 along the Atlantic Coast to Broward and the north- 

 ern edge of Dade County and down the Gulf Coast to 

 Collier County. 



Apparently South Florida has no local or endemic 

 tree species confined within the 3 southernmost 

 counties, according to current conservative 

 taxonomic references. This discovery was unex- 

 pected. However, at least 3 endemic varieties are 

 distinguished. Four endemic species (including 2 

 treelike cacti) were listed in the preliminary compi- 

 lation made in 1971. 



Several tree species from South Florida were 

 named as new by earlier workers. However, as a 

 result of additional studies, all tree species formerly 

 regarded as endemic in South Florida have now been 

 united as synonyms or varieties of species named 

 previously from the West Indies. 



Thus, all species of tropical trees native in South 

 Florida may be classed as border or peripheral 

 species. They are native also in foreign lands, mostly 

 in the Bahamas or Cuba or farther in the West Indies 

 or even elsewhere on the continent. Many are also 

 rare or local in Florida. Several, as indicated below, 

 are threatened with extinction or are endangered in 

 Florida and should have additional protection. How- 

 ever, if destroyed there, these rare native species 

 probably would survive through other populations 

 overseas. 



Three or possibly more taxonomic groups of tropi- 

 cal trees in South Florida are sufficiently distinct 

 from the nearest relatives to be distinguished by 

 scientific name as endemic varieties. These endemic 

 varieties and their distribution are summarized be- 

 low. 



Cereus robinii (Lem.) L. Benson var. deeringii 

 (Small) L. Benson (Cactus Succulent J. Am. 41: 126. 

 1969), Deering tree-cactus {Cephalocereus deeringii 

 Small, Pilocereus deeringii (Small) Kunth). Rare 

 and endangered and possibly nearly extinct. George 



Avery reports that he had looked for it in past years. 

 Upper Florida Keys, the type from Lower 

 Matecumbe Key, to the north end of Key Largo. Not 

 found on mainland. C. robinii var. robinii, the typi- 

 cal variety, is in the Lower Florida Keys and Cuba. 



Myrcianthes fragrans (Sw.) McVaugh var. 

 simpsonii (Small) R. W. Long (Rhodora 72: 23. 

 1970), Simpson stopper {Anamomis simpsonii 

 Small, Eugenia simpsonii (Small) Sarg., Myr- 

 cianthes simpsonii (Small) K. A. Wilson). Named as 

 a species by Small (1917), transferred to another 

 genus by Wilson (1960), and reduced to a variety by 

 Long (1970). Rare and local on mainland in Dade 

 County. Within Everglades National Park. Reports 

 from the Upper Keys need confirmation. Protected 

 by State law (as Eugenia simpsonii). M. fragrans 

 var. fragrans, the typical variety, known as naked 

 stopper, has a wider range in South Florida and 

 tropical America. 



Pinus elliottii Engelm. var. densa Little & Dor- 

 man (J. For. 50: 921, figs. 1, 2. 1952), South Florida 

 slash pine. This endemic variety is common and dom- 

 inant in pine forests of southern peninsular Florida 

 north along coasts to central Florida, farther north 

 than the tropical trees of this report, and also on 8 or 

 more of the Lower Florida Keys, including Big Pine, 

 Little Pine, No Name, Cudjoe, Ramrod, Big Torch, 

 Middle Torch, and Howe. Extinct on Key Largo in 

 Upper Florida Keys (Alexander 1953). Within 

 Everglades National Park and National Key Deer 

 Refuge and other preserves. This common large 

 tree of commercial importance for lumber was long 

 included under Pinus caribaea Morelet, Caribbean 

 pine, of Bahamas, Cuba, and Central America, and 

 at times also under P. elliottii Engelm., slash pine, 

 of southeastern United States, until separated and 

 named as a distinct variety (Little and Dorman 

 1952). Slash pine (typical variety), P. elliottii var. 

 elliottii, is widespread in the Coastal Plain of south- 

 eastern United States from central Florida north to 

 South Carolina and northwest to Louisiana. 



An explanation for the absence of endemic tree 

 species in South Florida is apparent. This peninsula 

 and the keys are relatively young geologically. 

 Though isolated from the main part of the continent 

 by the climate barrier, South Florida is relatively 

 near the Bahamas and Cuba. Thus, the West Indies 

 have been a seed source by water and air, especially 

 in hurricanes. Also, at the time of maximum glacia- 

 tion in the Pleistocene Epoch, the sea level was as 

 much as 200 feet lower and the land mass of the 

 Bahamas was several times as large as now. The 

 three endemic varieties suggest that some changes 

 are in progress and that a few new taxonomic groups 

 are originating. 



