Endangered Species Guidesheet

Geocarpon

Geocarpon minimum

Geocarpon, also known as "Earth fruit," is a tiny, inconspicuous plant found almost exclusively on sandstone glade outcrops. Presently, most of the known populations are located in Missouri, but it also occurs in Arkansas and Louisiana. Geocarpon is threatened by habitat destruction and modification, competition from non-native plant species, and lack of glade management. It is listed ENDANGERED by the Missouri Department of Conservation and THREATENED by the U.S. Fish and Wildlife Service.

Identification

The genus Geocarpon contains only 1 known species: Geocarpon minimum. It is a small, annual, succulent plant growing 1 1/2 inches tall. Young plants are dull green, sometimes tinged with red, and may become the color of red wine as the growing season progresses. The leaves are tiny and cup-shaped, growing opposite each other along the branches.

Geocarpon blooms from mid-March through early May. The flowers are green and inconspicuous, growing at the base of the leaves, and may appear to be leaves themselves. Fruits mature from May to early June. Plants die 4 to 6 weeks after seed set. The following December seeds germinate into tiny rosettes, which appear as a tiny cluster of leaves on the ground. The rosettes remain through winter and develop into mature plants the following spring.

For a technical description of this animal, refer to:

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

Habitat and Distribution

Geocarpon grows on Channel Sandstone glades and outcrops, many less than one acre in size. Within these glades, geocarpon thrives at the base of slightly tilted rock outcrops where seepage water flows across and forms shallow, sandy or gravelly depressions. These depressions usually contain a high amount of magnesium deposits and accumulate very little organic matter. Soil is often much thinner than the surrounding area (0 to 4 inches). Plants that grow away from sandy depressions and washes are crowded out by larger vascular plants.

Geocarpon populations in Missouri are restricted to Dade, Polk, Greene, Cedar, Jasper, Lawrence, and St. Clair Counties in the Ozark and Osage Plains Natural Divisions

Cause of Historic Decline

Geocarpon is restricted to widely scattered sandstone glades in southwest Missouri. As a result, this plant was historically rare. Historical changes in habitat resulting from the conversion of glades to pasture and the encrachment of fescue were reasons for the original concern and listing of this species. Recent surveys indicate that populations were lost as glades were converted to pasture, however, healthy populations still exist. Geocarpon has very specific habitat requirements. Its continued survival is dependent on appropriate glade management. Landowners can take an active role in protecting and properly managing sandstone glade habitats.

Current Threats To Geocarpon

• Conversion of glades to cool season pastures Converting glades leads to increased siltation into the sandy depressions where geocarpon is found. Once fescue and other introduced grasses becomve established in these depressions, the compete with geocarpon for space and nutrients. Overgrazing may also lead to decreased glade habitat quality by making it easier for woody plants to invade glades.
• Lack of periodic prairie grassland fires Historical fires probably helped reduce invasion by woody plants and the accumulation of leaf litter. Accumulation of leaf litter from trees in or around glades leads to a build up of soil.
• Off-road vehicles Many geocarpon sites are near roads and in open, easily accessible areas. Off-road vehicles can cause soil erosion that causes siltation and loss of suitable habitat, as well as directly crushing the plants.

Protection and Management: Steps Toward Recovery

In Missouri, geocarpon has always been restricted to Channel Sandstone glades. It apparently will not grow under any other natural conditions. Recovery of this plant will be achieved by protecting and managing existing populations and their glade habitat.

Some geocarpon populations have been harmed by the conversion of prairie grasslands to cool season grasses and by high levels of erosion caused by grazing. When possible, exclude stock from glady portions of the pasture if geocarpon is present.

• Managing geocarpon populations is as simple as good glade management. Promote land management activites that reduce encroachment by woody vegetation, eliminate the threat of competition with exotic plants, minimize soil erosion, and encourage a divers, native flora. Prevent the loss of glade habitat from highway construction and urban development by avoiding channel sandstone glades entirely, or plant to leave them as open space.
• Use prescribed fire as a management tool to remove leaves, dead grass, and accumulated organic matter. A prescribed fire is a useful management tool when conducted in the late summer or fall at 3 to 5 year intervals. Prescribed fires are best conducted while fescue and other exotic plants are green and photosynthesizing, but no so late that geocarpon seeds have germinated. August through September are probably good months for controlled burns.
• Reduce the spread of woody vegetation on channel sandstone glades that support geocarpon. Woody encroachment is an uncommon problem on channel sandstone glades. If the glade is being invaded by cedars or multiflora rose, cut and remove vegetation from the glade and treat rose stumps (cedar stumps will not sprout) with Round-Up to prevent sprouting. The objective is not to remove all trees, as oaks and other native species are part of the glade community, but to reduce or eliminate invasive woody species and exotics when they compete with geocarpon.
• Control introduced grasses like fescue and cheat grass. Established fescue threatens geocarpon populations at some sites. Late fall applications of Round-Up, followed by prescribed fire, provide control. September and October are good months to spray, especially after the rest of the glade flora have gone dormant. Because soil disturbance may stimulate fescue seed germination, annual treatments may be necessary until the fescue is eradicated. Avoud herbicide use during the growing period (December through March). Herbicide use is probably not a threat to geocarpon when applied July through September.
• * Herbicide Note * The timing of herbicide application is critical. No herbicides should ever be applied after seed germination (December) until plants complete their annual growth. For more information about timing herbicide application please contact the Missouri Department of Conservation or the Natural Resources Conservation Service.

---

Missouri and federal law prohibits the exportation, transportation, or sale plants on the State or Federal lists.

For more information on geocarpon, or to report sightings of this species, contact:

Endangered Species Coordinator or Natural History Division Botanist Missouri Department of Conservation Natural History Division P.O. Box 180 Jefferson City, MO 65102 (314)751-4115

For more information on pasture improvement programs or additional information about geocarpon or glade management, contact:

Your Local Natural Resources Conservation Service Office

---

---

Document ID: --
Content revision: --

• Main Nature Page