Washington University in St. Louis
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About the Tyson Research Center

Flora

Species lists, along with photos of some species, are available by clicking on the buttons below. In addition, a general description of the various plant communities found at Tyson can be viewed at the bottom of this page.

Vascular Plants (Ferns, Pines, Monocots, Dicots) - over 550 species.
Fungi - View a list of mushrooms and other fungi - over 60 species.
Algae - section incomplete
Lichens

GENERAL DESCRIPTION OF FLORA:

M. Zimmerman and W. L. Wagner surveyed the plants of Tyson Research Center and published the results of their analysis in 1979. (A Description of the Woody Vegetation Of Oak-Hickory Forest in the Northern Ozark Highlands, Bulletin of the Torrey Botanical Club 1106(2):117-122). Three remarkably distinct types of vegetation were identified and described. The following table summarizes this study:

Vegetation Type:

Dominant Species:

Moisture Levels:

Species Diversity:

Species Richness:

Basal Area per Tree:

Bottom Lands

Ulmus rubra
Platanus occidentalis

Mesic

H'=2.04

4.8

133.3 sq. cm

Protected Slopes

Cornus florida
Quercus alba
Quercus velutina

Less mesic

H'=1.95

6.2

103.4 sq. cm

Exposed South- Facing Slopes

Juniperus virginiana
Quercus muehlenbergii

Relatively xeric

H'=1.94

7.0

100.3 sq. cm

In this analysis, the authors state, "Although the vegetation at Tyson has been disturbed during the early portion of this century, forest regeneration has proceeded to an advanced state. The total basal area of trees over 10cm diameter at breast height is within the range reported for mature Eastern deciduous forest..."

They also comment, "...there is a very strong correspondence between the seedlings present in each habitat and the adult trees present in each habitat. This implies that self-replacement is occurring and that the habitats may be considered stable."

These observations apply to the forest which occupies roughly 85% of Tyson's 2,000 acres and which is situated on either side of the central valley of the property, which earlier was the site of munitions storage activities. The first-time visitor to Tyson's oak-hickory forest will normally remain primarily on the roads which occupy the tops of ridges. From here one commonly notices trees which have been damaged by lightning and severe winds. The soil in exposed areas is thin and the rates of tree growth and leaf litter accumulation are reduced. Here, and in the other habitats, the dominant species mentioned in the chart above are augmented by over thirty varieties of elm, maple, hickory, hackberry, walnut, ash, dogwood, cherry and locust, as well as numerous understory trees, shrubs, vines and forbs.

Scattered throughout the property, on west and south exposures, are a number of senescent or old glades. Here the canopy is scanty or lacking entirely. Winds and intense incoming solar radiation in summer contribute to xeric conditions. Indicator species include Quercus muehlenbergii, Q. stellata, Q. marylandica, Celtis tenuifolia, Juniperus virginiana and Ilex decidua. The herbaceous layer over the limestone/dolomite substrate is characterized by numerous species of Solidago and Aster, Gaura biennis, Houstonia longifolia, Parthenium hispidum, Erysimum capitatum and Opuntia compressa. The main herbaceous indicator species over the chert substrate are: Tephrosia virginiana, Vaccinium vacillans, Cunila origanoides, Gerardia grandiflora and G. pedicularia.

Toward the southwest corner of the property are extensive areas of cedar trees, overlying the Burlington Escarpment, and representing a somewhat different glade-like situation. The canopy here is approaching closure.

Representation of the bottomland vegetation community may be found in Mincke Hollow, in the valley south of Twin Ponds, in the north-facing valley near the Terry photo blind and, in remnant condition, in the central Tyson Valley along the main road. Overstory trees typical of this community include: sycamore, cottonwood, box elder, hackberry and bitternut hickory.

Throughout the Tyson Research Center property, the varied herbaceous vegetation contributes to the botanical richness. The inventory of vascular plants totals 548 species. Most of these taxa are represented in the Tyson Herbarium which has been assembled through the much-appreciated efforts of Erna Eisendrath (deceased) and her colleagues known as the "Tyson Toilers" (Catherine Filla, Susie Russell, Ann Ruger, Doris Neibaum, Sandy Posen, Sharon Petter, and Hal Bunting.) This collection is located near the Tyson Administrative Office which can arrange for herbarium access, upon special request.

In order to maintain habitat diversity in areas which have already been significantly manipulated, selected sections of Tyson are maintained as fields by mowing, most of them at least once a year.

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phone: (314)-935-8430
fax: (314)-935-8433
6750 Tyson Valley Road
Eureka MO 63025