Endangered Species Guidesheet

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OZARK WAKE ROBIN

Trillium pusillum var. ozarkanum

The Ozark wake robin is a woodland trillium. Its flowers consist of three white to pink petals above three green sepals. The plant grows seven to ten inches tall. It can be found in woodlands, usually on slopes. The species is listed RARE by the Missouri Department of Conservation.

Identification

The Ozark wake robin is a perennial herb in the lily family. Individual plants grow seven to ten inches tall. The slender, solitary stems are dark green with a purplish tinge near the ground. They grow from a thickened rhizome.

The flower is conspicuous because of three flower petals surrounded by three similar green sepals. Its three leaves grow around the stem in a circle. Leaves are dull or grass green, 3/8 to 1 inch wide and 1 5/8 to 3 3/8 inches long. They are blunt or rounded at the tips. A single flower blooms at the end of a short stalk above the circle of leaves. Flower petals are pure white when the flower opens, gradually turn pink, then turn a deep rose color as they shrink with age.

The Ozark wake robin can be distinguished from other trillium species by having narrower leaves. The sepals, which are modified leaves immediately beneath the petals, have five instead of three prominent veins. The Ozark wake robin is the only trillium in southwest Missouri with a stem between the leaves and the flower. All other species have the flowers attached immediately above the leaves.

For a technical description of this plant, refer to:

Steyermark, J. A. 1963. Flora of Missouri. Iowa State Press. Ames, Iowa. 1728 pp.

Life History

The Ozark wake robin blooms from early April through May, generally before the trees leaf out.

Fruits develop from May to mid-July. The fruit is pale yellow-green and oval or round.

Studies have shown that seeds are dispersed by ants. Germination may require up to two years. Young plants may grow three to six years before they reach flowering stage.

Habitat and Distribution

Ozark wake robin grows in the shade typical of upland hardwood forests of the southern Ozarks of Missouri. It occurs in cherty, acidic soils of oak-hickory forests, usually growing on slopes.

The Ozark wake robin is known from Barry, Lawrence, Shannon, and Howell counties in Missouri. Historically it was also known from McDonald and Taney counties.

It is a rare and local species with most populations concentrated in the Cassville area of Barry County. One population is protected on public land.

Recent population counts indicate that the number of plants per site ranges from four to several thousand.

Populations of this rare plant are also known from Arkansas, Oklahoma and Kentucky.

Cause of Historic Decline

Ozark wake robin populations may have declined from habitat loss and degradation. Heavy grazing has affected some populations.

Current Threats to Ozark Wake Robin

• Habitat loss and destruction Clearing of woodlands for conversion to pasture may threaten some populations. Near developed areas, competition from aggressive exotic plant species may alter habitat such that it is no longer suitable for the Ozark wake robin.
• Forest management techniques Complete forest canopy removal increases competition from undesirable weeds and shrubs. The Ozark wake robin is unlikely to survive in full sunlight. Group selection or single tree harvest would have less impact on this species. Mechanical site preparation following clear cutting should be avoided to protect the soil around Ozark wake robins.
• Grazing Grazing forests and woodlands where Ozark wake robin occurs should be avoided. Livestock may eat some of the plants. Others will be trampled as the livestock pass through the area. Many plants may be destroyed before they can produce seeds.
• Overutilization Overutilization is not a current threat, but the Ozark wake robin has a popular appeal among wildflower gardeners. Because it takes several years for them to mature, low-cost plants in nurseries may have been harvested from the wild and should not be purchased.

Protection and Management: Steps Toward Recovery

Only one population of Ozark wake robin is protected on public land. Private landowners have a very important role in protecting this rare species.

• Habitat improvement Existing oak woodlands containing Ozark wake robin should be protected. Private landowners should consider protection agreements or conservation easements with the Department of Conservation.
• Forest management techniques Complete forest canopy removal should be avoided in areas where Ozark wake robin occurs. If timber harvest is necessary, select single trees for cutting. The canopy cover should be maintained to provide shade for the Ozark wake robin.
• Grazing Cattle should be excluded from this plant's habitat during the growing season, which is March to June.
• State and Federal agencies All populations should be monitored for fluctuations in population numbers. Landowners should be informed of the value of this species in hopes that they will offer some protection to the plant.

Written by Charlene M. Bessken

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Missouri and federal law prohibits the importation, transportation, sale, purchase, taking or possession of plants on the State or Federal lists. For more information on Ozark wake robin, or to report sightings of this species, contact:

Endangered Species Coordinator or Botanist Missouri Department of Conservation Natural History Section P.O. Box 180 Jefferson City, MO 65102 (573) 751-4115

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