Cyperus squarrosus Linnaeus var. squarrosus . Awned Flatsedge. Phen: May-Oct. Hab: Moist depressions and seepages on granitic and other rocks, drawdown riverbanks, swales, shores, coastal rock barrens, other moist disturbed sites, cracks in sidewalks and pavement. Dist: Nearly cosmopolitan in distribution, in Old World and New World. The distribution of C. squarrosus var. squarrosus in precolonial North America is very uncertain.

ID notes:Similar to the closely related C. granitophilus (see key).

Origin/Endemic status: Native

Taxonomy Comments: Lowe & Carter (2023) interpret C. squarrosus as having three varieties, var. squarrosus, var. runyonii, and var. graniticus.

Synonymy: = Lowe & Carter (2023); = Cyperus aristatus Rottb. var. aristatus – Tx; = n/a – Tat; < Cyperus aristatus Rottb. – GW1, RAB; < Cyperus inflexus Muhl. – F, S, WV; < Cyperus squarrosus L. – Ar, C, ETx1, FNA23, GrPl, Il, K1, K3, K4, Mex, Mi, Mo1, NcTx, Pa, Tn, Va, WH3

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Wetland Indicator Status:

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

Heliophily: 9