Texas Trillium blooms in March at Mercer's conservation nursery.
Mercer Arboretum & Botanic Gardens is one of 38 leading botanical gardens and arboreta in the United States that collectively maintain over 750 species for the Center for Plant Conservation’s (CPC) National Collection of Endangered Plants. The CPC preserves rare, native (American) plants in a centralized network of botanical institutions within 17 states and the Virgin Islands. In Texas, Mercer Arboretum & Botanic Gardens, San Antonio Botanic Gardens, and The Lady Bird Johnson Wildflower Center share the responsibility for the preservation of rare plants within seed banks or as live specimens. In addition to the CPC institutions mentioned above, The Arboretum at Flagstaff and the Desert Botanical Garden of Arizona maintain the rare mountain and desert species for Texas. To preserve the nation’s rare botanical treasures, Mercer and the CPC’s other member institutions hold partnerships with concerned citizens, private and government conservation organizations, universities, and colleges.
In 2000, the CPC assigned Mercer the maintenance of the Texas trillium, which is over-collected from the wild and under threat from loss of habitat. The name trillium indicates that the arrangement of the flower parts and leaves are in groups of threes. Trilliums, often known as trinity lilies, wake-robins, or wood lilies, are unique spring-blooming wildflowers that form large localized colonies by means of their underground stems and by the germination of their seed.
Found in the Piney Woods of East Texas and in northwestern Louisiana, Texas trillium stands up to 12 inches tall, bears one or three leaves in whorls, and each petal that is 1.25 to 1.5 inches long begin as snow-white and then blush pink to magenta as they age. They complete flowering in the spring and rest during the hot months as underground stems. Shoots reappear from these perennial plants in late winter to early spring in shady, low, and moist wooded stream-banks and sphagnum bogs (baygalls) often with sweetbay magnolia, red maple, black gum, wax myrtle, and Virginia sweetspire trees.
The 43 species of trilliums that grow in North America and Asia are considered by gardeners as among the most beautiful of wildflowers and sentinels of spring by outdoor enthusiasts. Once considered a part of the lily (Liliaceae) family, trilliums are now included in the bunchflower family (Melanthiaceae) due to their unique characteristics. All trilliums bear a whorl of three leaf-like bracts below three colored petals. The showy flowers serve as signals to their pollinators and the odor of the flowers vary among the species. Trilliums with sweet smelling flowers signal to butterflies, bees, and wasps, whereas species like stinking trillium (T. foetidissimum), the Latin word for fetid or foul, of Louisiana and Mississippi signal to their pollinators, the flies. Species including the stinking trillium that are pollinated by flies often have dull brown or maroon flowers and the smell mimics rotting flesh. Often called birthwort, beth root or Indian balm, certain trilliums contain chemicals that are used medicinally as astringents, coagulants, expectorants and uterine stimulants. The plants, however, are generally considered toxic.
Partners assisting Mercer with the maintenance of the Texas trillium for the CPC include Stephen F. Austin State University, the Texas Nature Conservancy, the Coastal Crossroads Chapter of the Texas Native Plant Society, Lady Bird Johnson Wildflower Center, and Texas Parks & Wildlife Department (TPWD). Mercer’s conservation volunteers and partner biologists monitor wild populations for the Texas Natural Diversity Database Program and help collect seed stock for the CPC National Collection of Endangered Plants. The Texas Natural Diversity Database Program is a member of NatureServe, an international network of natural heritage programs and conservation data centers found in all 50 U.S. states, Canada, Latin America and the Caribbean.
In addition, Ohio’s Cincinnati Zoo & Botanic Garden’s Center for Research of Endangered Wildlife (CREW), also a certified CPC participating institution, has worked in partnership with Mercer for several years. CREW applies state-of-the-art technology to preserve the genetic diversity of rare exotic and native animals and plants. Dr. Valerie Pence heads the plant tissue culture and cryogenic (long-term freeze storage) laboratories.
Several of the rare plants maintained at Mercer including the Texas trillium are a challenge to propagate. All trilliums are notoriously difficult to germinate from dry seed. Reportedly, one batch of dry seed requires over 20 years to germinate after planting! Fresh seed from trilliums usually require two spring seasons to germinate and require several years of growth prior to bloom. Because of this, Dr. Pence and CREW are developing methods to generate cultures of trilliums from sections of the underground stems and from the embryos within fresh seed. Mercer has successfully coaxed Texas trilliums to bloom within the conservation section of the shade nursery (see photo), and is testing short-term storage techniques of the underground stems by extending their dormancy at refrigerated temperatures.
Future plans at Mercer include developing a public display of rescued Texas trilliums in the Endangered Species Garden that displays a number of America’s native endangered plants on a seasonal basis. In 2004, Texas Parks and Wildlife and the National Wildlife Federation awarded Mercer’s Endangered Species Garden the Best of Backyard Habitats certificate. In 2009, the North American Butterfly Association certified the garden as a butterfly garden. Mercer’s Endangered Species Garden serves as an educational tool for the importance of “wildscaping,” demonstrating the use of permanent water and food sources, composting, and organic management methods to benefit wildlife. Common native plants complement the rare species in this display garden and provide examples for home landscapes.
Adapted from Harris County Precinct 4’s Parkscape, Summer 2002
Anita A. Tiller, Botanist
Mercer Arboretum & Botanic Gardens
Photo by Anita Tiller
Updated February 28, 2012
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