Acer rubrum Linnaeus var. trilobum Torrey & A. Gray ex K. Koch. Section: Rubra. Carolina Red Maple, Swamp Maple, Water Maple. Phen: Jan-Mar; Feb-Jun. Hab: Wetlands, especially peaty, acid sites. Dist: Primarily a Southeastern Coastal Plain variety, the range of var. trilobum is unclear, possibly extending well inland and northward.

ID notes:Fall color yellow, orange, to red.

Origin/Endemic status: Native

Taxonomy Comments: Var. trilobum (as broadly defined) has greatly increased in abundance in the Coastal Plain of our area because of fire suppression and mechanical disturbance of peaty wetlands. Former large pocosin tracts, such as the Dismal Swamp, are now largely dominated by this tree. Molecular studies (Saeki et al. 2011) show a strong signal of a Floridian molecular entity, probably correlated morphologically with densely pubescent leaf undersurfaces and small, elongate, barely even trilobed leaves, centered in the Florida peninsula and extending northwards to an unknown degree, but apparently strictly Coastal Plain and deeply southeastern. An apparent second entity, somewhat intermediate between the Floridian entity and var. rubrum, has a more extensive distribution northwards, and a strong but not complete association with wetland habitats. The appropriate taxonomic treatment of (and nomenclature to apply to) these entities remains uncertain.

Synonymy: = F, Il, K1, K3, K4, NY, Tat, Tx, Murray (1970); = Acer rubrum L. var. tridens Alph.Wood – SFla; = Rufacer carolinianum (Walter) Small – S; < Acer rubrum L. – C, GW2, NcTx, NE, Pa, RAB, S13, Tn, Va, WH3; < Acer rubrum L. var. rubrum – Ar, G, Mo2

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Wetland Indicator Status:

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

Heliophily: 5