Guara angustifolia

Guara angustifolia, or Southern beeblossom, is a tall, slender plant with narrow leaves that spreads by rhizomes and can collect in dense stands. The drooping flowers emerge along the stems. The annuals are common in dune areas, meadows and grasslands.

References
Duncan, W. H., & Duncan, M. B. (1987). The Smithsonian guide to seaside plants of the Gulf and Atlantic coasts from Louisiana to Massachusetts, exclusive of lower peninsular Florida. Washington, D.C: Smithsonian Institution Press.