Was worried that this might be an introduced ornamental Allamanda sp., but I think the ID is good. The foliage looks right for the Angadenia, and wrong for Allamanda. I have a better shot I can upload, although this shows it reasonably well. Was finding it hard to believe that I had actually photographed a rare plant! -- the Angadenia is listed as threatened in Florida -- but see below. Was also worried that the habitat wasn't right: although this is the county in which the plant occurs, I don't think this area was pinelands. Photo was taken somewhere along the main park road between Mrazek Pond and West Lake, which the park map ( www.nps.gov/ever/planyourvisit/upload/evermap.pdf ) lists as either coastal marsh or mangrove. The background in this photo looks like grassland (which would mean the marsh), although along the road there were some small bare trees that a trio of kingbirds were perched in. I had stopped for the birds, which included a Western Kingbird, and took a quick snap of this large, showy roadside wildflower. I had no idea it might turn out to be something interesting! In fact, it looked so much like the Allamanda that I had seen cultivated in Tahiti that I figured it was an escaped ornamental.

I'm thinking that since the road is raised above the surrounding land, the soil immediately along it will be supporting a different plant community -- perhaps, in this case, pinelands plants. The pinelands are the most upland of the Everglades' habitats -- if anything here can be said to truly merit the term 'upland'. The pinelands are probably several feet higher than the coastal marsh here -- which is huge in an environment where 6" in elevation difference can lead to a completely different plant community.

Aha! Someone who clearly has a lot more experience photographing the Everglades than I do says the following: "Despite its local abundance [in pinelands], it is a state-listed threated species in Florida due to its small range." www.drewfulton.com/galleries/displayimage.php?album=1&amp...

So with both the habitat and the commonness now addressed, I'm happy with the ID. Input always welcome!