Vascular Plants of North Carolina
Account for Coastal Plain Dawnflower - Stylisma patens   (Desrousseaux) Myint
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Section 6 » Order Solanales » Family Convolvulaceae
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Author(Desrousseaux) Myint
DistributionPresent throughout the southern half of the Coastal Plain, including the Sandhills region. Ranges barely into the southeastern Piedmont. Occurs north to Wake and Greene counties.

This is a Southern species found north only to eastern NC, and south to northern FL and west to MS.
AbundanceFairly common to common in the Sandhills and in other areas southeast to Pender and Brunswick counties. Uncommon in the northern portion of the range. It is the most numerous of the five species of Stylisma in the state.
HabitatThis is another Stylisma of sandy soil, typically in pine/scrub oak sandhills, as are S. angustifolia and S. humistrata. Of course, it also grows on sandy roadsides and other sandy clearings.
PhenologyBlooms from June to August, and fruits shortly after flowering.
IdentificationThis is a slender herbaceous vine, trailing on the ground to about 3-4' long. It has alternate and somewhat slender leaves, somewhat oblong to lanceolate, about 1-1.5" long but about 1/4" wide. From the axils grow 1-3 small flowers, on stalks around 1" long, each white flower being funnel-shaped but barely 4/5" long and across. There are several similar species, also prostrate like this. S. patens has leaves mostly about 4-6 times as long as wide, as opposed to about 7-15 times as long as wide in S. angustifolia, which has linear leaves. Also, S. patens has quite hairy sepals, whereas those of S. angustifolia are glabrous. The quite rare S. pickeringii has even narrower leaves, about 2" long but barely 1/10" wide, essentially needle-like, and usually stiffy erect; its flowers are also quite erect and have villous sepals. S. humistrata also grows in sandy places like these others but its leaves are about 1/2" wide and the flowers grow 3-7 (on average) in a cluster instead of mainly just singly. Biologists who work in the sandy parts of the southern Coastal Plain are probably familiar with all four of these and can identify each without much problem, even by the leaves. However, for many other people, you may have to collect or measure a leaf or look at the sepals or other characters to be sure. As mentioned in Abundance, this may well be the first Stylisma you encounter, particularly in the Sandhills region.
Taxonomic CommentsSome botanists have moved S. angustifolia out from this species. Others still retain the latter as a subspecies or variety, however. All Stylisma species were formerly named as Bonamia species.

Other Common Name(s)Common Dawnflower, Sandhill Dawnflower, Sandhill Morning-glory
State RankS4
Global RankG5T3T5 [G3G5]
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