Vascular Plants of North Carolina
Account for Large White Fringed Orchid - Platanthera conspicua   (Nash) P.M. Brown
Members of Orchidaceae:
Members of Platanthera with account distribution info or public map:
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Section 5 » Family Orchidaceae
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Author(Nash) P.M. Brown
DistributionThis taxon is a recent split from Platanthera blephariglottis. Most references list it as a variety, but Weakley (2018) and a few others give it full species status. Though many herbaria do now have specimens labeled as P. conspicua, what percentage of the specimens labeled as P. blephariglottis are really P. conspicua, as opposed to the new taxon of that name? Here we map only specimens that have been annotated by experts. In general, this is the more widespread of the two White Fringed Orchid taxa in NC, occurring mainly across the southern half of the Coastal Plain. It is scattered northward to the VA line, and there are a few occurrences in the southern Mountains. In the Sandhills region, the strict sense P. blephariglottis is supposedly the form found there, according to the map in the revision paper. However, some plants there exhibit spurs intermediate in length and thus suggest P. conspicua - see image below from Moore County - but additional study is needed.

This is the southern taxon/species of the White Fringed Orchid group, ranging north only to eastern NC, south to southern FL, and west barely to eastern TX. There are a few occurrences into the mountains and Piedmont, but it is essentially a Coastal Plain species (as are many members of the genus).
AbundanceGenerally uncommon (to locally fairly common in well-managed preserves) in the southern half of the Coastal Plain, but rare and quite local in the northern half of that province. Rare to perhaps locally uncommon in parts of the Sandhills, but as P. blephariglottis also grows there, the abundances of the two there are not settled. Extremely rare in the southern Mountains. As with most orchids of savanna habitats, it is declining owing to fire suppression and loss of habitat. The NCNHP added this species to its Watch List (W7) in late 2022. Their State Rank of S2S4 indicates uncertainty about the identification of this form from the very similar P. blephariglottis, which were both contained within this latter name until recently. The website editors suggest a State Rank of S3?.
HabitatThis is a species of savannas and wet flatwoods, but it can occur in ditches and a few other disturbed damp but sunny sites. It is also found in streamhead pocosin ecotones and seepages.
See also Habitat Account for Wet, Sandy, Fire-maintained Herblands
PhenologyBlooms mostly in August and September in NC, somewhat later than P. blephariglottis where both occur together. Fruits somewhat soon after flowering.
IdentificationThis is one of the more spectacular wildflowers of the NC Coastal Plain, being easily spotted from long distances across a savanna when in full bloom. Plants grow mostly to 2-2.5 feet tall, with several strongly ascending and shiny leaves emerging from the lower part of the stem. As with all other members of the genus, you must see it in bloom for identification. This taxon, the taller and larger-flowered of the two White Fringed Orchids, has a conical and somewhat open inflorescence of several dozen large white flowers; the flower cluster is typically 4-6 inches tall. The lip projects forward and has fairly long and delicate fringes, and the long spur averages 1.5-2 inches long. The very similar P. blephariglottis,, with which it was recently split, has a shorter and denser inflorescence, a flower lip that has denser fringes, and flower spurs often less than 1 inch long.
Taxonomic CommentsThis taxon was formerly included within P. blephariglottis (broad sense) until recently. Many references, including Flora of North America, list it only as a variety -- P. blephariglottis var. conspicua -- whereas Weakley (2018) and a few others have raised it to full species status. Note that nearly all NC Platanthera species were formerly within the genus Habenaria.

Other Common Name(s)White Fringed Orchid (now used for the combined two taxa). As these are split out, a modifier name is needed, and thus this is typically named as Large White Fringed Orchid and P. blephariglottis (strict sense) as Small White Fringed Orchid. Southern White Fringed Orchid is another common name.
State RankS2S4 [S3?]
Global RankG5T4 [G4]
State StatusW7
US Status
USACE-agcpFACW link
USACE-empFACW link
County Map - click on a county to view source of record.
Photo Gallery
Larry ChenDare County mainland, August 2021, Alligator River NWR. DarePhoto_natural
B.A. SorrieMoore County, 2006, Eastwood powerline at NC 73.

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