Flora of the Southeastern United States

Panicum amarum Elliott var. amarum. Common name: Bitter Seabeach Grass. Phenology: Aug-Nov (-Jul). Habitat: Coastal dunes and shores. Distribution: RI and CT south to FL, west to se. and e. TX, south to the Caribbean coast of Mexico and Belize, restricted to the coast.

ID notes: Panicum amarum var. amarum and P. amarum var. amarulum are similar and sometimes confusable. They differ in general growth habit (long-rhizomatous with single stems in P. amarum var. amarum vs. short-rhizomatous with dense multistem tufts in P. amarum var. amarulum); foliage color (glaucous blue-green in P. amarum var. amarum vs. green or yellowish green in P. amarum var. amarulum); and panicle architecture (narrow, contracted, and spikelike in P. amarum var. amarum vs. wider and more divergently many-branched in P. amarum var. amarulum). Although the two sometimes co-occur in Coastal dune systems, P. amarum var. amarulum is primarily a plant of secondary dunes and inland sands while P. amarum var. amarum is most abundant on foredunes, upper beaches, and overwash flats (Virginia Botanical Associates 2023).

Origin/Endemic status: Native

Taxonomy Comments: See note under P. amarum var. amarulum.

Synonymy ⓘ: = K4, Meso6, Pa, Va, Lelong (1986); = Panicum amarum Elliott — C, F, G, HC, RAB, S, Tat; = Panicum amarum Elliott ssp. amarum — FlGr, FNA25, NE, NY, POWO, Zuloaga & Aliscioni (2023); < Panicum amarum Elliott — Mex, WH3; Panicum amarum Elliott. Basionym: Panicum amarum Elliott 1816

Links to other floras: = Panicum amarum ssp. amarum - FNA25

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Wetland Indicator Status:

• Atlantic and Gulf Coastal Plain: FAC (taxonomic split from wetland indicator species)
• Eastern Mountains and Piedmont: FACU (taxonomic split from wetland indicator species)
• Great Plains: FACU (taxonomic split from wetland indicator species)
• Northcentral & Northeast: FACU (taxonomic split from wetland indicator species)

Heliophily ⓘ: 9