Return to the Subtropics

We left the Lower Rio Grande Valley on Dec. 1 and headed for Florida, where we plan to wait a couple months for our new truck to be manufactured and for the worst of the COVID crisis in El Paso to pass. Camping in most of Florida in winter virtually requires reservations far in advance. We thought things would be easier this year with Canadians not being able to drive their RVs across the border, as they constitute a significant percentage of winter visitors. But this reduction was fully compensated by the number of campgrounds that were still closed due to COVID-19 and, incredibly, the number that were open but had closed their restrooms for the duration. With difficulty, while still in Texas, I was finally able to book sites almost continuously through the first week of January.

We mostly drove for 6 days, with breaks in the Florida Panhandle to hike on the lovely Clear Creek Nature Trail, near Whiting Naval Air Station, and to canoe on Kennedy Creek, in Apalachicola National Forest. We used Highlands Hammock State Park, in the middle of the Florida Peninsula, as a base from which to explore Lake Wales Ridge and its fascinating plant communities. This ridge, composed of relict white sand islands, is the only portion of Florida that remained as dry land during the high sea level two million years ago, and it served as a refugium for plants, with some having western affinities. We explored this area in 2018, but visited two new sites this time: McLean Cabin Trail in Lake Wales Ridge State Forest, and Hickory Lake Scrub in Frostproof. We also explored Lake June-in-Winter State Park in much more depth than in 2018; this small preserve might be the best white sand habitat we’ve seen. In total we found a remarkable 16 new plants species among these three sites!

One day was devoted to a long drive to the Atlantic Coast to look for Clusia rosea, the Autograph Tree. (It is so called because the succulent leaves discolor when bruised, so it is possible to “write” on the leaves with a sharp stick or other implement, and the writing shows up as brown against green a day or so later.) This is the only representative of the family Clusiaseae occurring in North America (north of Mexico). There are some very early records from south Florida, which lead most botanists to conclude that it did originally naturally occur in Florida, but the story has been made quite complicated by the subsequent widespread planting of the attractive species. It is possible that Clusia was extirpated in the state and that all plants now are descended from plantings, but the Atlas of Florida Plants accepts as likely natives the plants in a few counties, and the authority we follow, the Biota of North America Program (BONAP), does the same. So for our quest to see as many native North American vascular plant families as possible, we needed to see a tree in an accepted county, that impressed us as having the appearance of a natural occurrence.

The Atlas of Florida Plants cited one recent accepted specimen record with a precise enough location to pursue, rather far north on the coast, in Sebastian, FL. We found this plant with no trouble; it was a venerable tree, with about seven major trunks, rooted just above mangroves in sandy muck. It was clearly very old, and growing in a place where it would be unlikely to have been planted, so we happily checked it off our list. Eight days later we saw another robust Clusia in the Florida Keys, also growing just above mangroves, this time on bare limestone bedrock. Though close to plantings, it still seemed a good candidate as a natural occurrence, especially given its location within what is thought to be the original “core range” of the species.

With weekend reservations very difficult to arrange in state parks, we spent one weekend in Big Cypress National Preserve, where it is almost always possible to find a site without utilities on the spur of the moment. From here we spent one day canoeing on the Turner River. This is normally a gorgeous paddle through twisting mangrove tunnels, the branches being festooned with epiphytic plants, primarily bromeliads in the genus Tillandsia. But massive late summer rains had left much of the Everglades flooded, and with the river two feet higher than normal, the “roofs” of the tunnels were so low we could not sit upright in the canoe for more than a few seconds at a time, for a period of an hour. We met only one boat in the tunnels, in which one fisherman hunkered over in the bow, steering, while the other lay on his back in the bottom of the boat, propelling them by grabbing the overhead branches and pulling! It  was like watching someone climb a jungle gym, only sideways and upside down. But it did appear to be quite effective!

Our most exciting adventure while in the southwestern peninsula was getting together with naturalist Mike Owen in the Fakahatchee Strand Preserve. As I wrote in a 2018 bog post: A strand is a long and narrow swamp with directional water flow at least during wetter times of year. Fakahatchee Strand is the largest in Florida (20 miles long), and it has more species of orchids than anywhere else in the U.S. Most are epiphytic, and occur where Pond Apple (Annona glabra) and Pop Ash (Fraxinus caroliniana) trees form a dense enough forest canopy to trap moisture evaporating from the swamp water surface. This creates an extremely humid and therefore essentially frost-proof micro-climate (because of the high heat capacity of water vapor). This is a perfect situation for epiphytic orchids, bromeliads, and others.

Our target was one of the “others”: Peperomia obtusifolia, the least rare member of family Piperaceae in North America. Mike took us and preserve volunteer Gordon into a spectacular slough. We waded into water that was 30 inches deep and slowly moved father into the swamp, having to feel our way through the tannin-stained water to avoid tripping over submerged tree trunks. One must watch for Water Moccasins and Alligators, which are common here. To see the most interesting epiphytes, it is necessary to get into deep water because these are the areas that still have some water left, and therefore remain humid, even at the driest point in the year (typically early September). It took about twenty minutes to reach the Peperomia, which had an immature inflorescence, a nice bonus! With Piperaceae checked off, we now have just 7 native families left of 239. Along the way we saw the four least rare orchids of the swamp, Prosthechea cochleata, Epidendrum anceps, E. nocturnum, and E. rigidum, as well as the most famous species in the swamp, the Ghost Orchid (Dendrophylax lindenii). Of these, only the Prosthechea was in flower. We finished at deep dusk and counted it as one of the highlights of the year!

While staying in Collier-Seminole State Park, we paddled on the Blackwater River and on Halfway Creek, walked the lovely Royal Palm Hammock Trail several times, and recorded bats. Some of our more exciting moments were seeing a flock of 60 Wood Storks soaring high in the sky, taking advantage of the thermals, and recording Northern Yellow Bat for only the second time. We next headed for the Florida Keys, where we visited some of the best sites from 2018 (Windley Key Fossil Reef, Key Largo Hammock, Big Pine Key), and pretty much all the remaining prime areas for native plants in the Keys that we did not have time to visit in 2018. The best of the latter group were Crane Point Hammock in Marathon; Torchwood Hammock on Little Torch Key; and the Golden Orb Nature Trail in Long Key State Park.

We had a good haul of 20 new plant species while in the Keys, of which an amazing twelve represented new genera! The rarest plant we saw was Consolea corallicola, the Semaphore Cactus. Originally restricted to the Keys, it is now thought to occur naturally only within Torchwood Hammock, to which Patti Snyder of The Nature Conservancy was kind enough to give us the lock combination. On Long Key, we had a great walk on the Golden Orb Nature Trail. The highlight on the bay side was seeing Schoepfia schreberi, Graytwig, in flower, a big deal, as we had previously seen only one single non-flowering shrub of this species, which is the only U.S. representative of family Schoepfiaceae. Upon reaching the ocean side, there were a bunch of species in flower in the sandy soil a bit above the high tide line. Having seen nothing like this elsewhere, and given the somewhat overgrown and weedy appearance of the assemblage, I expected that they would all turn out to be alien species, but in fact they were native – five new species and three new genera in no more than one hundred meters of trail!! Other enjoyable aspects of our visit to the Keys were excellent views of the conjunction of Jupiter and Saturn, coffee on the beach for Eileen, and great seafood and key lime pie takeout.

Our last ten days in southern Florida, including Christmas and New Year’s Day, were spent in the Everglades. Unlike in 2003, 2004, and 2018, nearly our entire time in South Florida was really too hot and humid to be pleasant. The exceptions were a few days following each of two cold fronts that passed through, one of which arrived while we were camped at Flamingo. This encouraged us to spend a few quiet days just in camp, enjoying being comfortable again. Our best bird was in our campsite: a male Whip-poor-will that never called, but for several nights sat on top of the fruit of a mahogany tree (Sweitenia mahogani), sallying out to catch passing moths, and then returning to the same perch, like a flycatcher! I have never before seen behavior like this from any nightjar.

One day we paddled the Hell’s Bay Canoe Trail, a favorite, and found about seven bizarre, leafless vines (one possibly twenty feet long) that turned out to be a rare native orchid, Vanilla barbellata. The thick stem is green and presumably photosynthesizes sufficiently to replace the function of the short-lived leaves of the species. We also paddled on the Nine Mile Pond Canoe Trail, which had too little water, even in this exceptionally wet year. But on this outing I finally identified a bromeliad that had puzzled us in 2003 and 2004, as Catopsis berteroniana, a new genus for us.

Some trails were flooded but we did hike for half a day on the Coastal Prairie and Bayshore Trails and did short jaunts on seven other trails. The Anhinga Trail had a beautiful Purple Gallinule that consented to being photographed. The Pinelands Trail was short but had exceptional botanical diversity. At the Flamingo Marina we saw a Crocodile and several Short-tailed Hawks. Last but not least, we visited the Nike Missile Site within Everglades National Park, constructed following the Cuban Missile Crisis. This was especially poignant for Eileen, as her late father was a colonel in the army, working in the area of air defense artillery. He had direct experience with the Hercules missiles housed at the missile site.

One last note: having visited the Lower Rio Grande Valley of Texas, and the southern portion of Florida, one right after the other, I was struck by how many plant species were found in both places – the only two subtropical regions of the U.S. – without being found in between (e.g., along most of the Gulf Coast). This suggested to me that these plant species colonized the U.S. twice, once via Mexico (to Texas) and once via the Caribbean (to Florida). However, I recently read how, during major glacial periods of the last two million years, sea level dropped so low (as much as 300 feet), that the Gulf of Mexico receded drastically. This left a broad shelf of land along the whole Gulf Coast, allowing subtropical plants and animals to migrate fairly directly northeast from the Yucatan Peninsula to Florida, without having to deviate much to the north. How remarkable!