Vascular Plants of North Carolina
Account for Delta Arrowhead - Sagittaria platyphylla   (Engelmann) J.G. Smith
Members of Alismataceae:
Members of Sagittaria with account distribution info or public map:
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Section 5 » Order Alismatales » Family Alismataceae
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Author(Engelmann) J.G. Smith
DistributionAn odd NC distribution, only known so far from 5 counties in the Piedmont. First found in NC in 2008, and in Virginia in 1998.

This is a species of the lower Mississippi and Gulf drainages, found primarily north to central TN and OK, and south to AL and central TX. Scattered records from states on the Atlantic seaboard show little ecological pattern, and the species is likely not native here. Weakley (2018) says that the species "may be introduced, either by humans or by waterfowl".
AbundanceVery rare in its Piedmont range, with only a handful of known collections. The website editors have given each record a Provenance Uncertain status, to match the NCNHP's State Status of W4 -- Watch List but perhaps not native in the state. The NCNHP's rank of SU (Undetermined) is adequate, though is seems best to suggest SE?, as it is likely adventive at such wetlands, perhaps spread by waterfowl.
HabitatThis species in the state occurs in man-made wetlands, such as margins of farm ponds, ditches, and marshes at reservoirs.
PhenologyBlooms from June into September, and fruits shortly after flowering.
IdentificationThis species looks much like the reasonably common coastal species -- S. lancifolia. It has moderately large basal leaves, with petioles of 1 foot or more, and lanceolate or narrowly elliptical blades that average 4-6 inches long and about 1.5-2 inches wide. The flower stalk can grow up to 2 feet tall, with 3-8 whorls of flowers. In this species, several whorls are branched, giving it a rather broad inflorescence. The 3 white petals give the flower a spread of over 1 inch across. In this species, the fruiting pedicels strongly turn downward after flowering. Thus, an arrowhead with a moderately broad but lanceolate blade, growing in a Piedmont disturbed wetland, such as a pond margin, might well be this species, considered as a weed in some places, and certainly of uncertain provenance in most Atlantic Coast states.
Taxonomic CommentsThis taxon, now generally considered as valid, was formerly included as a part of the S. graminea complex. RAB (1968) named it as S. graminea var. platyphylla.

Other Common Name(s)Broadleaf Arrowhead, Delta Duck-potato
State RankSU [SE?]
Global RankG5
State StatusW4
US Status
USACE-agcpOBL link
USACE-empOBL link
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Harry LeGrandBig Lake margin, Umstead State Park; Wake County; 23 June 2021 WakePhoto_provenance_uncertain
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