Trillium sessile L.

Wake Robin


CC = 5
CW = 5
MOC = 62

© SRTurner

Family - Liliaceae

Habit - Perennial forb from short rhizomes.

Stems - Erect, to 30 cm, purplish (at least at base), glabrous.

Leaves - Whorled, 3 per plant, sessile, 5-9 cm long, usually about 2 times longer than wide, broadly elliptic to broadly ovate, the tips usually rounded, glabrous, usually not or only slightly mottled, the upper surface lacking stomates or with only a few near the tip, entire.

Trillium_sessile_leaf1.jpg Leaf, adaxial.

© SRTurner

Trillium_sessile_leaf2a.jpg Leaf, abaxial.

© SRTurner

Trillium_sessile_leaf2.jpg Leaf bases (abaxial).

© SRTurner

Trillium_sessile_leaf.jpg Leaf.

© DETenaglia

Inflorescence - Single sessile flower terminating the aerial stem.

Flowers - Erect, sessile. Sepals 3, spreading to ascending at flowering, 20-25 mm long, lanceolate to narrowly ovate, sometimes purplish tinged. Petals 3, 15-36 mm long, erect or nearly so, lanceolate to narrowly elliptic, broadest at or below the middle, narrowed at the base but the stalklike portion absent or less than 2 mm long, usually maroon, glabrous, erect. Stamens 6, 12-20 mm long, half or more than half as long as the petals. Filaments purple, 2-3mm long. Anthers long, yellow-brown. Ovary superior, 3-locular, with 6 angles or wings.

Trillium_sessile_flower.jpg Typical red flower.

© DETenaglia

Trillium_sessile_petals.jpg Petal, widest below middle.

© SRTurner

Trillium_sessile_flower4.jpg Flower, stamens more than half as long as petals.

© SRTurner

Trillium_sessile_flower2.jpg Greenish flower.

© DETenaglia

Trillium_sessile_flower3.jpg Yellow-green flower.

© DETenaglia

Trillium_sessile_stamens.jpg Stamens.

© DETenaglia

Fruits - Erect berries.

Flowering - April - June.

Habitat - Mesic and bottomland forests on lower slopes and bottoms of valleys and ravines.

Origin - Native to the U.S.

Lookalikes - Other species of trillium, especially T. viride, T. viridescens, and T. recurvatum.

Other info. - This fine species can be found mainly in the lower 2/3 of Missouri. The plant is fairly common in the habitats mentioned above. In appearance it is quite similar to its lookalikes, but can be distinguished by sepals which are spreading (not reflexed), petals which are usually deep reddish and broadest below the middle, and stamens that are at least half as long as the petals.

The flowers of this species have a fetid aroma, presumably to attract flies or beetles as pollinators. Species of Trillium are sometimes used in gardens but should never be dug from the wild. Not only does this practice adversely impact wild populations, but transplanted specimens rarely survive the experience. Gardeners should take care to purchase plants only from reputable nurseries which raise plants from seed or by rhizome divisions of existing stock.

Relatively uncommon plants with green flowers sometimes occur sporadically within populations and have been called form viridiflorum Beyer.

Photographs taken at Eagle Bluffs Conservation Area, Boone County, MO., 3-27-04, and at Rock Hill Park, Columbia, MO., 4-18-04 (DETenaglia); also at Bootleg Access, Washington County, MO, 4-7-2020 and 4-6-2021 (SRTurner).