Vascular Plants of North Carolina
Section: Common Name: Scientific Name: Family:
Account for Savanna Panicgrass - Phanopyrum gymnocarpon   (Elliott) Nash
Members of Poaceae:
Only member of Phanopyrum in NC.
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Section 5 » Order Cyperales » Family Poaceae
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Author(Elliott) Nash
DistributionOuter and Middle Coastal Plain.

Southeastern VA to OK, south to FL and TX. Mostly in the Mississippi River embayment.
AbundanceRare to uncommon, but perhaps overlooked due to its riverine swamp habitat. May form colonies via surficial stolons. This is a Significantly Rare species.
HabitatBlackwater cypress-gum swamps and back-up channels; brownwater floodplain swamps and other low woods.
PhenologyFlowering and fruiting August-October.
IdentificationThe stems and branches usually sprawl on the substrate (often mud) and take root at nodes, and may extend up to 3 feet long. The inflorescences are about a foot long, with stiffly ascending or spreading branches. The pointed spikelets are 5.5-7 mm long and arranged in 2 ranks on the inflorescence branches.
Taxonomic CommentsA synonym is Panicum gymnocarpon, which several authors prefer. The fertile lemma is only 1/3 the length of the sterile lemma, but more than half the length in all other Panicum and Dichanthelium taxa.

Other Common Name(s)Nearly all references name it as Savanna Panicgrass, a terrible name, as it does not grow in savannas but basically grows in swamps. Weakley (2018) uses Swamp Phanopyrum as one name. It should be named as Swamp Panicgrass, which is not used for any other species in our region. However, the website editors must yield to the majority and use Savanna Panicgrass as the most prevalent common name!
State RankS2
Global RankG5
State StatusSR-O
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