Vascular Plants of North Carolina
Account for Sidebeak Pencil-flower - Stylosanthes biflora   (L.) Britton, Sterns, & Poggenburg
Members of Fabaceae:
Only member of Stylosanthes in NC.
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Section 6 » Order Fabales » Family Fabaceae
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Author(L.) Britton, Sterns, & Poggenburg
DistributionEssentially statewide, but absent or nearly so in the extreme northeastern counties. No records yet east of Gates, Perquimans, Washington, and Beaufort counties. Scarce in the northern mountains.

This is a widespread species of the Southeastern US, ranging from PA and KS on the north to southern FL and central TX on the south. It has been recorded from most counties within this range.
AbundanceCommon to very common across the state, other than very rare to absent in the far northeastern counties and the northern mountains.
HabitatThis legume has about as varied habitats as any in the state. It occurs mainly in dry soil of woodland borders, old fields, powerline clearings, open woods, glades, margins of rock outcrops, and even into flatwoods and drier portions of savannas.
See also Habitat Account for General Dry-Xeric Glades and Barrens
PhenologyBlooms from June to August, and fruits from July to October.
IdentificationThis is one of the smaller native legumes in the state, with one to several erect stems but reaching only about 8-12 inches tall. The relatively few leaves are trifoliate, and the 3 leaflets are very narrowly elliptic, about 1.5 inches long for the terminal leaflet and shorter for lateral leaflets. Each leaflet tip has a slender nipple or extension, unusual for a legume species. At the tip of branches grow very small golden-yellow to orange-yellow flowers, each only about 1/4-inch across. Though the flowers are very few per plant and quite small, they tend to be slightly more orange-yellow (goldenrod color) than the standard yellow to bright yellow on many other legume species. This is a very frequently seen species across the state, often daily in walks along wooded borders, open dry woods, and other brushy places. When not in bloom, it can easily be overlooked; however, the quite narrow and dark green leaflets with the nipple/needle tip should be enough to identify it, as long as you are paying attention to small plants than grow well below knee-level!
Taxonomic CommentsSome references split the species out by varieties, though Weakley (2018) does not.

Other Common Name(s)Normally called just "Pencil-flower", but there are several other species in the genus in the country, and thus the common name for the genus is "pencil-flower". S. biflora is thus mainly known as Sidebeak Pencil-flower.
State RankS5
Global RankG5
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