Trillium | |
---|---|
Trillium erectum (red trillium) | |
Scientific classification | |
Kingdom: | Plantae |
(unranked): | Angiosperms |
(unranked): | Monocots |
Order: | Liliales |
Family: | Melanthiaceae |
Genus: |
Trillium L. |
Type species | |
Trillium cernuum L. |
|
Synonyms | |
|
Trillium (trillium, wakerobin, tri flower, birthroot, birthwort) is a genus of perennial flowering plants native to temperate regions of North America and Asia.
It was formerly treated in the family Trilliaceae or trillium family, a part of the Liliales or lily order. The APG III system includes Trilliaceae in the family Melanthiaceae, where can be treated as the tribe Parideae.
Plants of this genus are perennial herbs growing from rhizomes. They produce scapes which are erect and straight in most species. There are three large bracts arranged in a whorl about the scape. There are no true aboveground leaves. There are sometimes scalelike leaves on the underground rhizome. The leaflike bracts are photosynthetic and are sometimes called leaves. The inflorescence is a single flower. There are two subgenera. In T. subg. Trillium the flowers are mostly borne on a short stalk (pedicellate) whereas in T. subg. Phyllantherum the flowers are born directly on the bracts (sessile). The flower has three green or reddish sepals and usually three petals in shades of red, purple, pink, white, yellow, or green. There are six stamens at the center. There are three stigmas that are borne on a very short style, if any. The fruit is fleshy and capsule-like or berrylike. The seeds have large, oily elaiosomes.
Rarely, individuals have four-fold symmetry, with four bracts (leaves) and four petals in the blossom.
Accepted Species
Trilliums are myrmecochorous, with ants as agents of seed dispersal. Ants are attracted to the elaiosomes on the seeds and collect them and transport them away from the parent plant. The seeds of Trillium camschatcense and T. tschonoskii, for example, are collected by the ants Aphaenogaster smythiesi and Myrmica ruginodis. Sometimes beetles interfere with the dispersal process by eating the elaiosomes off the seeds, making them less attractive to ants.