Orchids naturalized in Florida

Abstract

Florida’s naturalized orchids are mostly terrestrials (10/15, 5/10 epiphytes), horticultural escapes (14/15), native to Asia (10/15), tropical American (4/10), and Africa (1/15). Only 3 species are widespread in Florida, Eulophia graminea, Eulophia maculata, and Zeuxine strateumatica, and can be considered invasive based on their spread beyond the areas of their initial establishments. Most of the other orchid species occur in one or two counties and have spread little so are considered naturalized but not invasive. The longest naturalized orchids (5/15) escaped more than 50 years ago, another group (5/10) more than 20 years ago, while the most recently naturalized species (5/10) less than 20 years ago. The 15 naturalized orchids comprise 12% (15/117 species) of Florida’s orchid flora, which is higher than most other places except for Hawaii’s (18/21) which has only 3 native orchids. Most orchids naturalized in Florida (10/15) have also naturalized elsewhere in the world. Failure to reproduce is the reason why most orchids don’t naturalize. To attempt to understand how Florida’s 15 naturalized orchids have overcome this barrier, the literature was examined to learn what their breeding systems and pollinators are in their native areas. This enabled predictions to be made about how these orchids reproduce in Florida. Four of the orchids need no pollinators because they are autogamous or apomictic. The native region pollinators of two of the orchids occur in Florida, five of the orchids are probably pollinated by congeneric species of their native area pollinators (Apis, Centris and Xylocopa), Two of the orchids are pollinated by close analogues of their native area pollinators (butterflies and hummingbirds). Overcoming other barriers to their naturalization, such as the lack of suitable mycorrhizal fungi or the inability to deal with abiotic limitations, has occurred but are poorly known and understood.