Live oaks, laurel oaks, magnolias, American holly, sparkleberry, and cabbage palms may be what come to mind in an oak maritime forest, but microhabitats host diverse and often surprising species. St. Catherines Island also has areas where pignut hickory dominates a high spot with scattered populations of bluff oak that are adjacent to pockets of red maples and sweetgums marking moist depressions.
wind-pruning_oak Magnolia Grandiflora  Pignut Hickory

Large amounts of discarded shells from Indian sites over centuries of deposition have created pockets of a distinctive soil throughout the island and its marsh hammocks that support a suite of shell loving plants. Deposits of shell not only sweeten the highly acidic soils typical of the Southern Coastal Plain, but also increase the moisture-holding capacity of the soil. Some of the plants growing on shell sites may need more basic soil, while others respond to the extra moisture. William Bartram remarked on the impact of shell deposits on the soil of the barrier islands in his book Travels Through North and South Carolina, Georgia, East and West Florida.

“This admirable beauty of the sea-coast-islands dwells in the humid shady groves, where the soil is made fertile and mellow by the admixture of sea shells.”
William Bartram (1773)

Plants Associated with Shell Deposits on St. Catherines Island

Angle pod (Gonolobus suberosus)
Carolina basswood (Tilia americana L. var. caroliniana)
Carolina laurelcherry (Prunus caroliniana)
Dwarf palmetto (Sabal minor)
Florida soapberry (Sapindus saponaria)
Florida swamp-privet (Forestiera segregata)
Four-angled flatsedge (Cyperus tetragonus)
Green dragon (Arisaema dracontium)
Hercules club (Zanthoxylum clava-herculis)
Red buckeye (Aesculus pavia)
Red mulberry (Morus rubra)
Southern red cedar (Juniperus virginiana L. var. silicicola)
Sugarberry (Celtis laevigata)
Spanish bayonet (Yucca aloifolia )
Tough-leaf dogwood (Cornus asperifolia)
Yaupon holly (Ilex vomitoria)
Yellow passionflower (Passiflora lute)


 

References:
Bartram, William, Travels Through North and South Carolina, Georgia, East and West Florida, Facsimile of 1792 London Edition, The Beehive Press, Savannah, Georgia 1973

Porcher, Richard Dwight and Douglas Alan Rayner, A Guide to the Wildflowers of South Carolina, University of South Carolina Press 2001

Edwards, Leslie, Jonathan Ambrose, L. Katherine Kirkman, The Natural Communities of Georgia, The University of Georgia Press 2013

Alan S. Weakley, Flora of the Southern and Mid-Atlantic States, UNC Herbarium, North Carolina Botanical Garden, University of North Carolina at Chapel Hill 2012