Vascular Plants of North Carolina
Account for Least Trillium - Trillium pusillum   Michaux
Members of Trilliaceae:
Members of Trillium with account distribution info or public map:
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Section 5 » Order Liliales » Family Trilliaceae
DistributionFound at widely scattered sites across the state, with large areas where certainly absent, such as most of the Piedmont and northern Mountains. Present in scattered sites in the Coastal Plain -- mainly in the Great Dismal Swamp area in the far northeast, and the vicinity of the Onslow-Pender county line border. Also found in a zone near the Fall Line (Piedmont and Coastal Plain transition) from Halifax southwest to Wake and Johnston counties. A handful of records for the southern half of the Mountains, plus an isolated record in the southern Piedmont (Anson County). These sites represent roughly four different taxa/forms. Weakley (2022) mentions also that the species is found in southwestern VA "within a kilometer of the Alleghany County, NC border, and the plant may be found to also occur in nw. NC".

A Southeastern species occurring at widely scattered and disjunct sites from VA and southern MO south to southern SC, southern AR, and eastern OK.
AbundanceRare in the Great Dismal Swamp vicinity and in Fall Line creek drainages from Halifax County southwest to Wake and Johnston counties. Very rare in the southern Mountains, and extremely rare elsewhere (but plants may be numerous where found, such as in Anson County). The species is considered as State Endangered, though technically it is the named varieties -- pusillum and ozarkanum -- that are each listed as Endangered; whereas the two unnamed varieties are listed by the NCNHP as Significantly Rare.
HabitatThis is a wetland species for the most part, generally occurring in damp ground in shady forests, such as in swamps, wet bottomlands, and edges of savannas over marl (Onslow and Pender counties only). In the Dismal Swamp it favors "floodplain islands", such as slightly raised land within the swamp itself. The montane variety occurs on "Dry to dry-mesic slopes, in NC under Quercus coccinea and Kalmia latifolia" (Weakley 2018). This last habitat is counter to where it grows eastward. There may be some affinity to grow in somewhat circumneutral or only very slightly acidic bottomlands and swamp islands.
PhenologyBlooms from late March to early May. The Fall Line populations tend to bloom in the first half of April. Fruits in June and July.
IdentificationThis is the most unmistakable species of trillium in the state owing to its dwarf size. It grows only about 3-5 inches tall, and the three elliptical green leaves average only about 2 inches long, with generally rounded tips. The 3 white petals are narrowly elliptic to lanceolate and about 1 inch long. The flower is essentially sessile, such that it generally faces upward, "sitting on top of the bases of the leaves". The 3 green sepals are about the same shape and size as the petals and thus look like miniature leaves. As there are four varieties listed in Weakley (2018), there is some variation in the petal size and shape, leaf width, and a few other characters; however, nothing looks at all like this species when seen in bloom. Observers often find many plants that don't flower, but these are immature plants that will not bloom until later years. As you might imagine, it is easy to walk past this species when not in bloom, as the plant is so close to the ground. Even so, the three narrow leaves, each at 120-degree angles to the others, render it easy to identify once you finally spot the first individual. And, the species can occur in fairly sizable colonies of a few hundred plants.
Taxonomic CommentsThere has been great inconsistency as to how many varieties or subspecies should be named within this this species; few references will offer the same number. NatureServe lists three varieties -- ozarkanum, pusillum, and virginianum. Weakley's (2022) flora lists four varieties -- the first two above, and the other two undescribed, as occurring in NC. The var. virginianum is known only from southeastern VA but not in NC. Note that back in the 1960s, RAB (1968) did not list varieties or subspecies for it.

Other Common Name(s)Dwarf Trillium, Dwarf Wake-robin, Little Trillium
State RankS2 *
Global RankG4
State Status[E]
US Status
USACE-agcpFACW link
USACE-empFACW link
County Map - click on a county to view source of record.
Photo Gallery
D. SchaferMerchants Millpond State Park; 17 March 2023 GatesPhoto_natural
Laurie RichardsonMerchants Millpond State Park; 27 March 2023 GatesPhoto_natural
B.A. SorrieAnson County, same data. AnsonPhoto_natural
B.A. SorrieAnson County, 2015, Pee Dee NWR, moist woods off Big Oak Road. AnsonPhoto_natural
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