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:
Google Images
Section 5 » Order Alismatales » Family Alismataceae
Show/Hide Synonym
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.

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 might not be 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. NHP has the State Rank as SH, but as SERNEC shows collections from 2008 and 2013, and there is a photo from 2021, the species is clearly still extant; the editors suggest S1?
HabitatThis species in the state occurs in man-made wetlands, such as margins of farm ponds, ditches, and marshes at reservoirs.
See also Habitat Account for General Beaver Ponds and Semi-natural Impoundments
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 RankSH [S1?]
Global RankG5
State StatusW4
US Status
USACE-agcpOBL link
USACE-empOBL link
County Map - click on a county to view source of record.
Photo Gallery
photographercommentsphoto_linkcountyobsType
Harry LeGrandBig Lake margin, Umstead State Park; Wake County; 23 June 2021 WakePhoto_natural
Select a source
AllHerbaria
Individual
Select an occurrence type
AllPhoto_naturalCollection_provenance_uncertainOther_provenance_uncertain