Mercer Botanic Gardens is one of the 38 leading botanical gardens in the United States that maintains the National Collection of Endangered Plants for the Center of Plant Conservation(CPC).

Over three fourths of the endangered plants in the United States occur in the highly diverse ecosystems of Texas, California, Florida, Hawaii, Puerto Rico, and the U.S. Virgin Islands. Mercer shelters over 24 rare plants and several of the plants are on display in the Endangered Species Garden.

To learn more about endangered plant species, stop by Mercer Botanic Gardens and ask the staff about these rare plants, and view them up-close in the Endangered Species Garden.

Founded in 1984, the CPC celebrated 25 years of plant conservation and preservation in 2009. Click the link below, “Restoring America’s Vanishing Flora,” to watch their anniversary video.

Restoring America’s Vanishing Flora

The Millennium Seed Bank (MSB) Project is a global plant conservation effort developed by the Royal Botanic Garden, Kew, United Kingdom. The MSB Project coordinates work by more than 30 organizations in 20 countries worldwide. Mercer Botanic Gardens partners with the MSB Project by hosting volunteer training sessions for east Texas collections. To learn more about the MSB Project and the Lady Bird Johnson Wildflower Center’s involvement as well as view some of Mercer’s volunteers in action, please click on the link below to watch an informative video.

Millennium Seed Bank Project Video

Endangered Species Garden

The Endangered Species Garden, a rare native plant garden, was founded at Mercer in 1994 through a donation by Star Enterprise. In 2002, the River Oaks Garden Club and The Mercer Society graciously supplied the funds to enlarge and renovate this unique garden. Renovated in 2002, the Endangered Species Garden is home to threatened or endangered annual and perennial native plant species, and serves as an important teaching tool to the more than 100,000 visitors to Mercer each year. A replica of a beaver dam and pond serve as the focal point for the woodland and wetland habitats, and common native plant species complement the rare native species on display.

Endangered Species Garden

Awarded the Best of Backyard Habitats certificate of merit by Texas Parks & Wildlife and the National Wildlife Federation in 2004, the 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 for the benefit of wildlife. The garden also routinely serves as an outdoor classroom for Master Gardener and Master Naturalist classes and workshops.

Take a self-guided tour of our Endangered Species & Native Plant Garden.

How You Can Help

From collecting endangered seeds in the wild to carefully cultivating and restoring a plant’s gene pool, plant conservation is exacting and costly.

Although Mercer receives annual maintenance funds from the Center for Plant Conservation to support plant restoration for several species, additional funding is needed to care for the remaining collection of threatened or endangered plant species.

Donations go to funding field equipment, travel costs, seed cleaning, packaging supplies, and horticultural supplies.

Become a Plant Sponsor

Sponsor an Endangered Plant Today!

Sponsoring an endangered plant species is a great way for individuals, families, clubs, and organizations to play an active role in conserving Texas plants. Sponsors choosing to honor someone special through a donation are recognized in Precinct 4 publications and events referencing their sponsored species, honored on plaques and signs at Mercer, and featured on Mercer’s website. Sponsors also receive national recognition from the Center for Plant Conservation headquarters at the Missouri Botanical Garden in St. Louis.

Sponsorship donations range from $200 to $10,000 for a single endangered species.

Become a Plant Sponsor

Restoration

Mercer has been working with the Center for Plant Conservation (CPC) since 1989 and is one of 38 botanic facilities in the nation that maintains CPC’s National Collection of Endangered Plants. Mercer provides technical guidance and assists with the restoration and maintenance of these rare plant populations. Mercer also serves as a rescue holding center for rare plants from local and out-of-state partners. Mercer staff and volunteers assist with rare plant monitoring, seed collection, and processing, as well as propagation and on-site maintenance.

For more information: www.centerforplantconservation.org.

Restoration
Conservation efforts include rescue, propagation, and restoration. At Mercer, volunteers clean seeds for storage or prepare them for germination. Seeds to be stored are packaged and frozen in a standard freezer and a subset is sent to the National Center for Genetic Resources Preservation, a national seed storage facility in Ft. Collins, CO.

Endangered Plant Species

*Sponsored Species*

Bog Coneflower

Plant Name: Bog Coneflower (Rudbeckia scabrifolia)

Partially sponsored by: Kingwood Garden Club

Status: On Texas rare plant watch list

Plant Family: Sunflower (Asteraceae)

Habitat: Angelina, Jasper, Newton, Sabine, and Shelby counties in TX and in Natchitoches, Sabine, Vernon, and Winn parishes in LA

Threats: Loss of habitat.

Description: The Bog Coneflower is found in seepage areas and bogs along hillsides and forests.

Corkwood*

Plant Name: Corkwood (Leitneria floridana)

Sponsored by: The Mercer Native Plant Team in memory of Art Pollet, and Edward K. Love Conservation Foundation of St. Louis

Status:On Texas rare plant watch list

Plant Family: Quassia (Simaroubaceae)

Habitat: Brazoria, Chambers (historic), Fort Bend, Galveston (introduced), Harris (introduced), and Jefferson counties in Texas. Also in AR, FL, GA, and MO

Threats: Loss of habitat

Blooms: Male and female flowers occur in late winter to early spring on separate trees. Fruits May through the summer.

Description: A small tree that inhabits coastal and inland wetlands

Correll's False Dragon-head

Plant name: Correll’s False Dragon-head (Physostegia correllii)

Status:On Texas rare plant watch list

Family: Mint (Lamiaceae)

Habitat: Historically occurs in Bexar and Montgomery counties. Extirpated from Gillespie County. Reported in Galveston, Kinney, Maverick, Travis, Val Verde, and Zapata counties in Texas. Occurs in one site in Louisiana in St. James Parish. Reported in Coahuila, Nuevo Leon, and Sonora states in Mexico.

Threats: Road widening, herbicide run-off, and channelization of ditches

Blooms:June through August

Description: P. correllii occurs in many diverse wetland habitats in its range. Recent tests at Louisiana State University’s Medical Plant Laboratory shows that extracts of this plant slow the growth of certain tumor cell cultures.

CPC Plant Profile

Glen Rose Yucca

Plant name: Glen Rose Yucca/Brazos River Yucca (Yucca necopina)

Status:On Texas rare plant watch list

Family: Agave (Agavaceae)

Habitat: Hood, Parker, Somervell, and Tarrant counties in Texas

Threats: Loss of habitat

Blooms: May

Description: Found in sandy areas and fencerows of North Central Texas

Houston Camphor Daisy*

Plant name: Houston Camphor Daisy (Rayjacksonia aurea)

Sponsored by: Lakewood Forest Garden Club; Crouch Environmental Services, Inc.; Suzzanne Chapman in honor of Blanca and William Othon; The Mercer Society, and Anita Tiller in memory of Michael H. Tiller; Aveda Cosmetics (2005)

Status:On Texas rare plant watch list

Family: Sunflower (Asteraceae)

Habitat: Harris and Galveston counties in Texas

Threats: Primary risk is urban sprawl

Blooms: October through November

Description: This rare annual occurs on local Texas prairies. R. aurea is a possible future candidate for drought-tolerant and deer-resistant gardening and is a nectar source for wildlife. Information: The U.S. Army Corps of Engineers’ Addicks and Barker Reservoirs in southwest Harris County and northeast Fort Bend County, The Katy Prairie Conservancy, Harris County, and Harris County Flood Control District properties currently are the best refuges for this plant.

CPC Plant Profile

Large-fruited Sand Verbena*

Plant name: Large-fruited Sand Verbena (Abronia macrocarpa)

Sponsored by: by The Quaker Hill Foundation (1990)

Status: Endangered

Family: Four O’clock (Nyctaginaceae)

Habitat: Freestone, Leon, and Robertson counties in east to central Texas

Threats: Development, oil drilling, and invasive plants

Blooms: March through May

Description: Long-lived, drought-tolerant, extremely fragrant at dusk perennial of sandy post-oak savannas. Pollinated by moths.

CPC Plant Profile

Long-sepaled False Dragon-head

Plant name:Long-sepaled False Dragon-head (Physostegia longisepala)

Status:On Texas rare plant watch list

Family: Mint (Lamiaceae)

Habitat: Hardin, Jasper, Newton, Orange, and Tyler counties in Texas, and Acadia, Beauregard, Calcasieu, and possibly Allen and Bienville parishes in LA

Threats: Loss of habitat

Blooms: May through June

Description: This perennial occurs in many diverse wetland habitats in its range.

Louisiana Quillwort

Plant name: Louisiana Quillwort (Isoetes louisianensis)

Partially sponsored by:The Woodlands G.R.E.E.N.; The Woodlands Garden Club; Mary Lou Klene in honor of Mr. and Mrs. A. Mercer Rogers; Blue Bonnet Garden Club of The Woodlands, TX; The Piney Woods Garden Club in Memory of George Flott; and Houston Cactus and Succulent Society

Status: Endangered

Family: Quillwort (Isoetaceae)

Habitat: Alabama, Louisiana, and Mississippi

Threats: Clear-cutting of stream banks and timber and sand/gravel mining

Blooms: Nonflowering species, reproduces by spores

Description: This primitive, nonflowering relative of the mosses, ferns, and horsetails is a living fossil. Found most often on sandbars in streams. Note: In October 2008, Mercer returned approximately 200 plants to partners with LA Natural Heritage, USFWS, and The Nature Conservancy for a trial restoration at Abita Creek, LA.

CPC Plant Profile

Navasota False Foxglove

Plant name: Navasota False Foxglove (Agalinis navasotensis)

Status:On Texas rare plant watch list

Family: Figwort (Scrophulariaceae)

Habitat: Grimes and Tyler counties in Texas

Threats: Road widening

Blooms: Summer

Description: Annual, partly parasitic on native grasses, and is a host plant for Buckeye butterflies. The A. Navasotensis occurs in open grassy areas.

Neches River Rose-mallow*

Plant name: Neches River Rose-mallow (Hibiscus dasycalyx)

Sponsored by:The Magnolia Garden Club of Beaumont, Texas in memory of Elinor Steinhagen Burrus, generous supporters of the Center for Plant Conservation’s Plant Sponsorship Program (2013).

Status:Species of Concern

Family: Mallow (Malvaceae)

Habitat: Cherokee, Harrison, Houston, and Trinity counties in East Texas

Threats: Herbicide run-off and loss of wetland habitat

Blooms: June through August

Description: Hibiscus is a host plant for butterflies including the Hairstreak. Plants are being reintroduced at the Davy Crockett National Forest.

CPC Plant Profile

Pondberry*

Plant name: Pondberry (Lindera melissifolia)

Sponsored by: by Mrs. Alice C. Fick of Auburn, AL in memory of Kenneth Beighley, and The Edward K. Love Conservation Foundation of St. Louis (2001)

Status: Endangered

Family: Laurel (Lauraceae)

Habitat: Occurs in one county each in AR, MO, MS, SC, and NC and is extinct from FL, AL, LA, and GA

Threats: Loss of habitat

Blooms: March through April and September through October

Description: This colonial, deciduous, aromatic shrub grows in a variety of floodplain habitats in its range. Female plants produce fruits (drupes) that are bright red at maturity. Lindera genus is a host plant for Spicebush Swallowtail Butterfly.

CPC Plant Profile

Prairie Dawn*

Plant name: Prairie Dawn (Hymenoxys texana)

Sponsored by: by The Garden Club of Houston, Kingwood Garden Club, The Mercer Society, and The John Koros Memorial (2004)

Status:Endangered

Family: Sunflower (Asteraceae)

Habitat: Harris, Fort Bend, Trinity, and possibly La Salle counties in Texas

Threats: Development and competition from other plant species

Blooms: March through April

Description: Prairie Dawn is tolerant of extreme ranges in salinity and water. Note: The U.S. Army Corps of Engineers Addicks and Barker Reservoirs in southwest Harris County and northeast Fort Bend County, The Katy Prairie Conservancy, Harris County, and Harris County Flood Control District properties currently may offer the best refuge for this rare prairie annual.

CPC Plant Profile

Rough-stem Aster

Plant name: Rough-stem Aster (Symphyotrichum puniceum var. scabricaule, synonym: Aster puniceus var. scabricaulis)

Partially sponsored by: Monte P. Gilliam; Friends and Family of Connie M. Shourd

Status:On Texas rare plant watch list

Family: Sunflower (Asteraceae)

Habitat: Anderson, Franklin, Freestone, Henderson, Hopkins, Smith, Van Zandt and Wood counties, Texas. Also occurs in four sites in AL, LA, and MS.

Threats: Drainage of its bogs/pond habitats

Blooms: October through November

Description: This perennial is a host for butterflies including the Painted Lady and serves as a nectar species.

CPC Plant Profile

Scarlet Catchfly

Plant name: Scarlet Catchfly (Silene subciliata)

Partially sponsored by: Bromeliad Society of Houston, Inc. Friends in memory of Lindsey Dianne Stowe

Status:On Texas rare plant watch list

Family: Pink (Caryophyllaceae)

Habitat: Hardin, Jasper, Jefferson (historic), Liberty, Newton, Polk, Sabine, Shelby, and Tyler counties in Texas, and Allen, Beauregard, DeSoto, Natchitoches, Sabine, and Vernon parishes in LA

Threats: Due to elimination of natural fire cycles, this perennial is under threat from competition by native woody plants and invasive exotics.

Blooms: July through October

Description: This perennial species is often found in oak-farkleberry sandylands in open woodlands and sand-hills.

Slender Gay-feather

Plant name: Slender Gay-feather (Liatris tenuis)

Status:On Texas rare plant watch list

Family: Sunflower (Asteraceae)

Habitat: Angelina, Hardin, Jasper, Newton, Orange, Sabine, San Augustine, and Tyler counties in Texas, and also LA

Threats: Certain kinds of logging and development. Also, due to elimination of natural fire cycles, this perennial is under threat from competition by native woody plants and invasive exotics.

Blooms: June through August

Description: This lovely perennial is found in well-drained sites in pine forests and on road-sides

Southern Lady’s-slipper Orchid*

Plant name:Southern Lady’s-slipper Orchid (Cypripedium kentuckiense)

Sponsored by: by the Virginia Native Plant Society and Anne A. Rowley in honor of Jocelyn Sladen’s birthday

Status:On Texas rare plant watch list

Family: Orchid (Orchidaceae)

Habitat: Cass, Nacogdoches, Harrison, Newton, Red River, Sabine, San Augustine, Shelby, and Tyler counties in Texas, and scattered throughout AL, AR, GA, KY, LA, MS, OK, TN, and VA

Threats: Certain kinds of logging, development, and collectors

Blooms: April through June

Description: Inhabits shady ravines in East Texas

CPC Plant Profile

Texas Golden Glade Cress

Plant name: Texas Golden Glade Cress (Leavenworthia texana, synonym: Leavenworthia aurea var. texana)

Status:Species of Concern

Family:Mustard (Brassicaceae)

Habitat:Inhabits the unique geological outcrop of the Weches formation in San Augustine and Sabine counties, and in an introduced site in Nacogdoches County, Texas

Threats:Destruction from open pit mining of glauconite-“green rock”-for road surface material. Due to elimination of natural fire cycles, this annual is also under threat from competition by both native woody and invasive plants.

Blooms:March through May

Description:Brassicaceae are native host plants for butterflies including the Whites. Information: The Weches formation creates “islands” of alkaline sediments within the surrounding acidic piney woods.

CPC Plant Profile

Texas Meadow-rue

Plant name: Texas Meadow-rue (Thalictrum texanum)

Status:On Texas rare plant watch list

Family: Buttercup (Ranunculaceae)

Habitat: Austin, Brazoria, Brazos, Fayette (historic), Grimes, Harris, Waller, and Washington counties in Texas

Threats: Loss of habitat

Blooms: January through March

Description: This perennial often occurs in partially shaded, damp, sandy soils in moist post-oak woodlands and also occurs in prairie habitats. A site at Willow Park is being restored by the City of Houston.

Texas Screwstem

Plant name: Texas Screwstem (Bartonia texana)

Status:On Texas rare plant watch list

Family:Gentian (Gentianaceae)

Habitat: Found in bog habitats along wooded streams in East Texas (Angelina, Hardin, Jasper, Nacogdoches, Newton, Polk, San Augustine, San Jacinto, and Tyler counties) and western Louisiana.

Threats: Loss of habitat

Blooms: September through November

Description: This annual member of the Gentian Family often grows among moss on exposed tree roots and logs.

Texas Trailing Phlox*

Plant name:Texas Trailing Phlox (Phlox nivalis ssp. Texensis)

Sponsored by: by The River Oaks Garden Club, The Mercer Society’s “Mercer Memorial Trust Fund,” David C. Berkshire, Carol Kobb in memory of Millie Guadino, Suzzanne Chapman in honor of her parents, Ann C. Baumer and Derek Chapman, and Anita Tiller in memory of her parents Ruth L. and Werner G. Tiller (2003)

Status: Endangered

Family: Phlox (Polemoniaceae)

Habitat: Occurs in the piney woods of Hardin, Polk, and Tyler counties in Texas

Threats: Due to elimination of natural fire cycles, this perennial is under threat from competition by native woody plants and invasive exotics.

Blooms: Spring

Description: A reintroduction is currently underway by the National Park Service for the Big Thicket National Preserve. Texas Trailing Phlox is a nectar source for wildlife and a possible future candidate for drought-tolerant gardening after it has been recovered.

CPC Plant Profile

Texas Trillium

Plant name: Texas Trillium (Trillium texanum or Trillium pusillum var. texanum)

Status:On Texas rare plant watch list

Family: Lily (Liliaceae), but Trilliums have recently been moved to the Death Camas Family (Melanthiaceae)

Habitat: Found in shady and acidic ravines, seeps, and bogs of Angelina, Cass, Cherokee (extinct), Harrison, Houston (historic), Jasper, Marion, Nacogdoches, Panola (historic), Rusk (extinct), Smith, and Wood counties in Texas, and northwestern parishes in Louisiana.

Threats: Development

Blooms: March through May

Description: The only Trillium in Texas with white, stalked flowers. Flowers age to pink and then reddish color.

Texas Windmill-grass

Plant name: Texas Windmill-grass (Chloris texensis)

Partially sponsored by:Cherry Hartig, Fort Bend County Master Gardeners, R. Jack Cagle in Memory of J. Neil Mask

Status:On Texas rare plant watch list

Family: Grass (Poaceae)

Habitat: Brazoria, Brazos (historic), Chambers, Galveston, Harris, and Nueces counties in Texas

Threats: Urban development of prairies, and invasion by exotic and native woody plants due to lack of natural fires.

Blooms: April through November

Description: This native grass is an important host plant for butterflies including the Satyr and Skipper. Note: The U.S. Army Corps of Engineers’ Addicks and Barker Reservoirs in southwest Harris County, northeast Fort Bend County, The Katy Prairie Conservancy, Harris County, and Harris County Flood Control District properties may currently offer the best refuges for this plant.

CPC Plant Profile

White Bladderpod*

Plant name: White Bladderpod (Physaria pallida, synonym: Lesquerella pallida)

Sponsored by: by Dr. and Mrs. Sellers J. Thomas, Jr.; Mr. Frank A. Liddel, Jr.; Dr. and Mrs. Charles F. Squire of Houston, and US Fish & Wildlife Service (1999)

Status: Endangered

Family: Mustard (Brassicaceae)

Habitat: Inhabits the unique geological outcrop called the Weches formation in San Augustine County, Texas

Threats: Destruction from open pit mining of glauconite-“green rock”-for road surface material. Due to elimination of natural fire cycles, this annual is also under threat from competition by both native woody and invasive plants.

Blooms: January through May

Description: Brassicaceae are native host plants for butterflies including the Whites.

CPC Plant Profile

White Fire-wheel

Plant name:White Fire-wheel/White Blanket-flower/Winkler’s Gaillardia (Gaillardia aestivalis var. winkleri)

Status:On Texas rare plant watch list

Family: Sunflower (Asteraceae)

Habitat: Hardin, Newton, and Tyler counties in Texas

Threats: Due to the elimination of natural fire cycles in the East Texas Piney Woods, this perennial is under threat from competition by native woody and invasive plant species.

Blooms: February through September

Description: Reintroduction is in progress at the Big Thicket National Preserve in southeast Texas. This plant is an important nectar source.

CPC Plant Profile