The story of Trillium ovatum

By Thembi Borras

Trillium ovatum is in bloom and the story of this species is worth sharing. Trillium ovatum can be found in moist coniferous forests and may be identified by an erect naked stem that supports 3 showy leaves in a single whorl subtending the equally showy 3 petal flower, the color of which begins white and ages to pink then purple. They are a long lived perennial, in fact you will not recognize them per this description until age 15.

In the first year the root radical develops, in the second year the cotyledon develops. One leaf emerges annually as the rhizome develops between ages 3 and 15. At age 15, 3 leaves emerge and the plant begins to flower. The rhizome of Trillium ovatum, also called a corm is a solid underground storage organ that accumulates annual scars that can be counted. Trillium ovatum as old as 72 years have been identified in our area, in the Eastern United States a closely related species of Trillium ovatum as old as 105 years has been identified.

The seed dispersal biology adds to this fascinating story. A mature plant produces seeds, to which a swollen oil rich body, called elaiosome, is attached, which attracts ants. Ants collect the seeds and transport it back to their underground nest, where they eat the elaiosome. The seed is ready to germinate having been cleaned and planted by the ants.

I was told this story in a presentation by Botanist Eric Jules during a Special Forest Products workshop in September of 1999. In the same presentation I also learned that after clearcutting, the survival of Trillium ovatum sharply declines, which it was suggested is, in part, due to the disruption of this cycle. It is thought the deer mice population increases. The deer mice eat the seed before the ants secure them.