An Illustrated Flora of the Northern United States, Canada and the British Possessions/Trilliaceae
Nat. Syst. ed. 2, 347.
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.|
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.
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.