July on St. George Island

Ceratiola ericoides, Florida Rosemary or Sand Heath Not actually a rosemary. This species leaches a chemical defense against pests and competition that creates a ring of bare sand around each plant. It is also a larval host for 2 seasonal forms of the Emerald Moth Caterpillar. (1) The leaves of this plant, like many other coastal scrub species, are needle-like, and have a waxy coating that offers protection from rapid evaporation.
Conradina canescens, Scrub or False Rosemary. Also not a rosemary, but at least this one is a member of the mint family, Lamiaceae…

Barrier islands are fantastic places to see fascinating plant and animal adaptations to dynamic, high disturbance conditions. St. George Island, located ~3 to 8 miles off of panhandle Florida’s (not really) forgotten Gulf coast, is presently about 28 miles long, with an average width of about 3/4 of a mile. It is part of a chain of islands that form the outer rim of Apalachicola Bay, one of the most biologically diverse and productive estuarine systems in the world. (the lower portion of the Apalachicola River basin was designated a UNESCO World Biosphere Reserve in 1983.)

Black-senna, Seymeria cassioides. This species is hemiparasitic to pine. If its roots make contact with pine roots, the plant grows quickly and completes its life cycle, although it is capable of reaching maturity without a pine host. (3)
These may be Florida harvester ants, Pogonomyrmex badius – hauling a False Rosemary flower to a subterranean nest. This species harvests seeds from a variety of plants, and stores them in damp chambers for consumption and larvae-feeding. (2). Although these ants will harvest seeds right off of living plants, they will dispose of the chaff in other chambers near the periphery of their nest. Perhaps that is what is happening here…?

Although St. George has been developed as a popular vacation spot, its ecology remains evident in natural areas across the island (various map links here), as well as many yards, roadsides, and ditches. These photos represent just a tiny cross-section of barrier island flora and fauna…

1. Whitney, Eleanor Noss., D. Bruce. Means, and Eryk Jadaszewski. Florida’s Uplands. Sarasota, FL: Pineapple, 2014. Print

2. Tschinkel WR, Kwapich CL (2016) The Florida Harvester Ant, Pogonomyrmex badius, Relies on Germination to Consume Large Seeds. PLoS ONE 11(11): e0166907. https://doi.org/10.1371/journal.pone.0166907

fruit of  Turtleweed or Saltwort, Batis maritima. This salt marsh/salt flat plant is a larval host for Southern white and Eastern pygmy blue butterflies.
Old lightning whelk shell, Sinistrofulgur sinistrum – found in a sand bar a few hundred yards offshore. Lightning whelks were a popular food source for early Native American communities along the Gulf coast. The shell’s unusual ‘sinistral’ (clockwise) spiral is thought to have had spiritual significance, representing cycles of the sun (east to west) and birth to death. The shells were modified for a variety of uses, from beads and gorgets (chest pendants) to a wide range of cutting tools. Lightning whelk shell vessels were used also for black drink (Yaupon, Ilex vomitoria) ceremonies. (4)

3. Grelen, H. E., and W. F. Mann. “Distribution of Senna Seymeria (Seymeria Cassioides) a Root Parasite on Southern Pines.” Economic Botany 27.3 (1973): 339-42. Web

4. Marquardt, William H., and Laura Kozuch. “The Lightning Whelk: An Enduring Icon of Southeastern North American Spirituality.” Journal of Anthropological Archaeology 42 (2016): 1-26. Web



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