Trillium: A Family to Call Its Own

All in the Family

By Marion Blois Lobstein, Botany Chair, Prince William Wildflower Society and Professor Emeritus- NVCC

One of the most beautiful and easily recognizable groups of spring wildflowers is the trilliums in the Trillium family (Trilliaceae), formerly in the lily family (Liliaceae). In northern Virginia, the more common trilliums are the sessile or toadshade trillium (Trillium sessile) and the rarer species is the large-flowered trillium (T. grandiflorum). Both of these species bloom a bit later than earliest spring wildflowers, with the sessile trillium beginning to bloom in early April (sometimes even late March) and the large-flowered trillium in mid-April to early May. Both species are found in rich, well-drained, deciduous woods. Sessile trillium is found in coastal plains, piedmont, and mountain geographic provinces from New York, Ohio, and Minnesota south into Georgia, Mississippi, and Arkansas, while the range of the large-flowered species is more often in mountains from southeastern Canada south into the mountains of the Georgia and Arkansas. Several other species of trillium can be found from Northern Virginia and/or farther west into Virginia mountains, including purple trillium (T. erectum), nodding trillium (T. cernuum), and painted trillium (T. undulatum).

The genus name Trillium is derived from the Latin word “tres” for three, which refers to the flower parts as well as the leaves that are in groups of three. The species epitaph,sessile, meaning “without a stalk” refers to the flowers of the sessile trillium that lack a pedicle (flower stalk) and grandiflorum, “large-flowered,” referring to the showy, large flowers of T. grandiflorum.  Other common names for T. sessile are toad or toadshade trillium, stalkless trillium, and sessile-flowered wake-robin. Another common name for T. grandiflorium is great white trillium. In some botanical manuals and popular wildflower guides, the trilliums are put into the separate family of the Trilliaceae and that convention is now followed in the new Flora of Virginia.

In the two trillium species on which this article focuses, a solitary flower bud develops after the leaves emerge from the underground rhizome.  Only mature plants will produce flowers. In both species there are three green sepals, three petals (which will be discussed in more detail), six prominent stamens, and a three-angled pistil. In the sessile trillium,upright petals average one to two inches in length, usually maroon, but also can be yellow-green. The upright petals of this species surround the stamens and pistil. The spreading white to pink petals of the large-flowered species are one to three inches long. Flowers are borne on a flowering stalk or pedicle that is one to two inches long.  In large-flowered trillium, the flower petals do turn pink as they age, but the color variation of pink flowers when the flower buds emerge and during the early flower development in this trillium seems to be a result of genetic variation.  The fragrance of the sessile trillium can range from musty to faintly carrion-like to fruit-like. Main pollinators are carrion flies and beetles, which push the petals apart to reach the stamens and pistils. The large flowered trillium has a more pleasant fragrance that attracts bee species, which are its primary pollinators.

The fruit that develops in both species is a six-angled, pulpy berry that is approximately one-half to three-quarters of an inch long. Inside the fruit that matures by late June are 15 to 20 oblong, russet-colored seeds three-sixteenths to one-quarter inch long, with a fleshy crest or elaiosome on the upper end of the seed. Fats in the elaiosome on the seeds attract ants that then disperse the seeds. The fats provide the ants a concentrated energy source. It may take two or more years for the seeds to germinate and up to seven years to have a plant that will bear flowers.

The characteristic broadly oval leaves of all trilliums occur in groups of three. The leaves of sessile trillium are mottled and average from one and one-half to five inches long, while those of the large-flowered trillium are not mottled and are two and a half to six inches long. The leaves die back or senesce after the fruit matures and seeds are shed. The stem height of sessile trillium is four to eight inches tall compared to eight to eighteen inches tall in the large flowered species. Both species have well-developed rhizomes with shallow fibrous root systems.

The medicinal and edible uses of trilliums as a group are many. The young leaves are edible raw or parboiled, however, in most areas today, trilliums ARE NOT COMMON enough to collect and eat. Medicinal uses of trillium rhizomes by American Indians and in folk medicine include inducing labor in childbirth and relieving bleeding following parturition, sore nipples, and female disorders. Trilliums also were used as an astringent to stop nosebleeds and internal hemorrhaging, as a poultice to treat sores, ulcers, insect stings, and even to treat diarrhea.  The Chippewa Indians washed rheumatic joints with an extract of trillium rhizomes then pricked the skin numerous times with a needle to “inject” the fluid into the area. Extracts of trillium rhizomes have purported astringent, expectorant, and even uterine stimulant properties.

The sessile trillium may be found in abundance at Great Falls Park (both Virginia and Maryland), at Riverbend Park, Balls Bluff Park, and other sites especially along the Potomac River. Large-flowered trillium is best seen from late April to early to mid-May at G. Richard Thompson Wildlife Management area near Linden, Virginia. It is estimated that at this site there are at least 18 million individual plants growing in a two square-mile area. It is breath-taking to see large-flowered trillium carpeting the forest floor at this site! Even though the sessile trillium is not as showy, its delicate beauty is well worth the effort to seek out this spring. Both these species are important and beautiful members of the “guild” of early spring wildflowers that carpet our rich deciduous woods.

[Images: Trillium grandiflorum (Michx.) Salisb., and Trillium erectum, both found in Flora Londinensis by William Curtis (1746-1799), accessed at University of Wisconsin-Stevens Point web site, http://wisplants.uwsp.edu; Trillium cernuum, in A Flora of North America by William P.C. Barton (1823), accessed at University of Missouri Library’s Special Collections and Rare Books, http://mulibraries.missouri.edu.]

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