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Weekly “What is it?”: Coastal Plain Honeycombhead & Gulf Coast solitary bee

Coastal plain honeycombhead blooms through the summer on local beaches. Photo credit, Bob Pitts, National Park Service

Over my years of leading people on interpretive trail hikes, I have learned it is particularly important to know the names of whatever happens to be in bloom. These flowers are eye-catching, and inevitably someone will ask what they are. In fact, one of my favorite wildflower identification books is categorized not by taxonomy, but by bloom color—with a rainbow of tabs down the edge of the book for easy identification.

Wildflower identification can be tough, but color-coded guidebooks are really helpful! Photo credit: Carrie Stevenson, UF IFAS Extension

In our coastal dunes right now, several plants are showing off vibrant yellow blooms. Seaside goldenrod, coreopsis, and other asters are common. Rarer, and the subject of today’s post, is the Coastal Plain Honeycombhead (Balduina angustifolia). It has bright yellow flowers, but often gets more notice due to its unusual appearance when not in bloom. The basal leaves are bright green and similar in shape and arrangement to a pine cone or bottlebrush (albeit a tiny one), sticking straight up in the sand. The plants are typically found on the more protected back side of primary dunes or further into secondary dunes, a little more inland from the Gulf.

When not in bloom, the plant resembles a green pinecone planted in the sand. Photo credit: Carrie Stevenson, UF IFAS Extension

The plant plays a special role in beach ecology, as a host plant for Gulf fritillary butterflies and the Gulf Coast solitary bee (Hesperapis oraria). The bee is a ground-dwelling pollinator insect that forages only in the barrier islands of Mississippi, Alabama, and Florida. The species is currently the subject of a University of Florida study (they’re out at Ft. Pickens right now), as the endemic bee’s sole source of nectar and pollen is the honeycombhead flower. As of publication date, no bee nests have been discovered. Researchers are interested in learning more about the insect’s life cycle and nesting behaviors to better understand and protect its use of local habitats. Based on closely related species, it is believed the Gulf Coast solitary bee builds a multi-chambered nest under the soft sands of the dunes.

Adult female Hesperapis oraria foraging on coastal plain honeycombhead (Balduina angustifolia). Photograph by John Bente, Florida Department of Environmental Protection, Florida Park Service.

While the honeycombhead plant is found in peninsular Florida and coastal Georgia, the bee has been identified only in a 100 km² area between Horn Island, MS, and St. Andrews Bay, FL. Luckily for the bee, large swaths of this land are preserved as part of Gulf Islands National Seashore and several state parks. Nonetheless, these coastal dune habitats are threatened by hurricanes, sea level rise, and development (outside the park boundaries).  Due to its rarity and limited habitat, a petition has been submitted to the Fish and Wildlife Service for protection under the Endangered Species Act.