Vascular Plants of North Carolina
Account for Sessile Trillium - Trillium sessile   L.
Members of Trilliaceae:
Members of Trillium with account distribution info or public map:
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Section 5 » Order Liliales » Family Trilliaceae
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AuthorL.
DistributionLimited in the state just to the upper floodplain of the Roanoke River, in Halifax and Northampton counties. SERNEC specimen records for other NC counties (i.e., Catawba, Forsyth, Rowan) are presumed misidentifications of T. cuneatum, if not transplants.

This is a primarily Midwestern trillium, with its abundance center in two separate areas: the Ohio River watershed area and the greater Ozark Mountains area. It ranges north from western NY to IL, and south to extreme northern NC east of the mountains, and to northern AL and eastern OK west of the Appalachians. It is not found in the southern Appalachians, and it is surprisingly scarce near the Mississippi River itself.
AbundanceLocally fairly common to common at a handful of sites along both the north and south sides of the upper Roanoke River. Surprisingly, not known elsewhere in rich floodplain soils farther upriver, such as along the Dan River, as it is found in the Dan River drainage in southern VA counties bordering NC. This is a State Threatened species.
HabitatIt is limited to rich soils along the Roanoke River, both on natural levees and on slopes. It grows under a hardwood canopy, and growing with it are a good handful of other rare plant species, such as Camassia scilloides, Enemion biternatum, and Urtica chamaedryoides.
See also Habitat Account for Coastal Plain Rich Wet-Mesic Alluvial Forests
PhenologyBlooms in March and April, and fruits a month or two later.
IdentificationThis is one of several "toadshades", species of trilliums with sessile flowers situated directly on top of the whorl of three mottled leaves. These leaves have some lighter green blotches and are very widely elliptic or ovate, about 4 inches long and nearly as wide. In fact, the leaves are almost rounded and leaf tips are not as acute as in most other trilliums. The three petals are erect and normally maroon-purple, only about 1 inch long, and generally elliptic. There are no other trillium species that occur in the Roanoke River area, and thus it is easily identified. Farther west, the quite similar T. cuneatum can be found; there could be the potential some day for either to be found in the Dan River drainage in Caswell or Rockingham counties. This latter species typically has more sharply pointed leaves, narrower petals, and has the stigma of the flower only as long as the ovary or shorter (whereas T. sessile has the stigma 1.5 times or more as long as the ovary). Both species can occasionally have yellow or greenish-yellow petals.
Taxonomic CommentsNone. This species was, surprisingly, not discovered before RAB (1968) went to press, despite it being readily found in a number of sites along the upper Roanoke River. (For whatever reason, this floristically exciting area was overlooked or ignored by early botanists, and essentially none of the rare species there were collected by the time RAB [1968] was published.)

Other Common Name(s)Toadshade Trillium, Sessile-flowered Trillium, Sessile-flowered Wake-robin, Toad Trillium. As many to most trillium species have common names as xxxxxx Trillium, it is best not to use idiosyncratic names like Toadshade, Wake-robin, Sweet Betsy, etc., if there are other and more descriptive names available.
State RankS1
Global RankG5
State StatusT
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