An Illustrated Flora of the Northern United States, Canada and the British Possessions/Trilliaceae

Family 24.   TrilliàceaeLindl.   Nat. Syst. ed. 2, 347.   1836.
Wake-Robin Family.

Somewhat fleshy herbs, perennial by rootstocks.  Leaves cauline, whorled, or sometimes solitary long-petioled ones are borne on the rootstock.  Flowers terminal, solitary or umbelled, sessile or pedicelled, perfect.  Perianth of 3 separate sepals and 3 separate petals.  Stamens 6; anthers 2-celled.  Ovary sessile, 3-celled; styles 3, stigmatic along the inner side; ovules several or numerous in each cavity.  Fruit a globose or 3-lobed berry.

Three genera and about 25 species, natives of the north temperate zone.

Leaves in 2 (rarely 3) whorls; flowers umbelled. 1. Medeola.
Leaves in 1 whorl; flowers solitary. 2. Trillium.


1.   Medèola   L.   Sp. Pl. 339.   1753.

A slender erect unbranched herb, loosely provided with deciduous wool.  Rootstock thick, white, tuber-like, with somewhat the odor and taste of cucumbers, the slender fibrous roots numerous.  Leaves of flowering plants in 2 whorls (rarely 3 whorls); lower whorl of 4-10 oblong-lanceolate or obovate leaves; upper whorl of 3-5 ovate or oval leaves, subtending, like an involucre, the sessile umbel of small greenish yellow declined flowers.  Perianth of 6 separate equal oblong recurved segments.  Stamens 6, hypogynous; filaments slender, smooth, longer than the oblong extrorse anthers, the sacs laterally dehiscent.  Ovary 3-celled; ovules several in each cavity; styles 3, recurved, stigmatic along the inner side.  Berry globose, pulpy.  [Name from Medea, a sorceress, referring to the supposed healing properties.]

A monotypic genus of eastern North America.


2.   Tríllium   L.   Sp. Pl. 339.   1753.

Glabrous erect unbranched herbs, with short scarred rootstocks and 3 leaves whorled at the summit of the stem, subtending the sessile or peduncled solitary bractless flower.  Solitary long-petioled leaves are sometimes borne on the rootstock.  Perianth of 2 distinct series of segments, the outer 3 (sepals) green, persistent, the inner 3 (petals) white, pink, purple or sometimes greenish, deciduous or withering.  Stamens 6, hypogynous; filaments short; anthers linear, mostly introrse. Ovary sessile, 3-6-angled or lobed, 3-celled; ovules several or numerous in each cavity; styles 3, stigmatic along the inner side.  Berry many-seeded.  Seeds horizontal.  [Latin, in allusion to the 3-parted flowers and the 3 leaves.]

About 24 species of North America and Asia. Besides the following, some 7 others occur in southern and western North America.  Known as Three-leaved Nightshade and Birthroot.  Phyllody, i. e., the reversion of petals or sepals to leaves, is occasional, and the floral parts are sometimes in 4's.  Type species: Trillium cernuum L.