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Xyris tennesseensis Kral
Tennessee Yellow-eyed-grass
Federal Protection: Listed Endangered
State Protection: Endangered
Global Rank: G2
State Rank: S1
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: Highest Conservation Concern
Element Occurrences (EOs) in Georgia: 16
Habitat Summary for element in Georgia: Seepy margins of limestone spring runs
Perennial herb usually occurring in small clumps. Its leaves are 5.5 - 18 inches (14 - 45 cm) long, 0.2 - 0.4 inch (0.5 - 1 cm) wide, erect, flat or slightly twisted, and with swollen, pink or purple leaf bases that overlap up to one-third the length of the blade and form a bulbous base. The flower stalk (scape) is 12 - 28 inches (30 - 70 cm) tall, straight (not spirally twisted), unbranched, ribbed, and slightly flattened in cross-section; the upper stalk is angled or winged; a reddish-brown sheath, shorter than the leaves, encircles the base of the scape. A single, cone-like flower spike, 0.4 - 0.6 inch (1 - 1.5 cm) long and bluntly oval, is held at the top of the flower stalk; it is composed of many tan, rounded, overlapping bracts; the spikes usually produce only 1 flower per day, from beneath the rounded tip of a bract. The flower has 3 oblong, yellow petals, 3 stamens, and 3 bearded staminodes; ovary and sepals do not show above the tip of the bract.
There are more than 20 species of Xyris in Georgia and they are all similar. Carolina Yellow-eyed Grass (Xyris difformis) has rough leaf surfaces and flat leaf bases. Twisted Yellow-eyed Grass (X. torta) has swollen leaf bases but its leaves are less than 0.2 inch (0.5 cm) wide, twisted, with strongly raised veins. Both may occur with Tennessee Yellow-eyed Grass.
Four rare species of Xyris occur in Georgia:
Xyris chapmanii (Chapman Yellow-eyed Grass, Special Concern) occurs in Fall Line streamhead seepage bogs. For more information, see: http://www.namethatplant.net/plantdetail.shtml?plant=2540
Xyris drummondii (Drummond Yellow-eyed Grass, Special Concern) occurs in pine flatwoods in Georgia's Fall and Coastal Plain ecoregions. For more information, see: https://www.georgiabiodiversity.org/portal/profile?group=plants&es_id=16101
Xyris scabrifolia (Harper's Yellow-eyed Grass, Special Concern) occurs in sedge bogs, pitcherplant bogs, and pine flatwoods in Georgia's Fall and Coastal Plain ecoregions. For more information, see: https://www.georgiabiodiversity.org/portal/profile?group=plants&es_id=15562
Xyris tennesseensis (Tennessee Yellow-eyed Grass, state and federal Endangered) occurs in seepy margins of limestone spring runs in northwest Georgia. For more information, see: https://www.georgiabiodiversity.org/portal/profile?group=plants&es_id=17987
Sunny, wet habitats over calcareous bedrock such as spring runs, edges of shallow streams and ponds, seeps, and wet meadows in northwest Georgia.
Tennessee Yellow-eyed Grass reproduces sexually by seeds as well as vegetatively by lateral buds that develop in the axils of leaves at the base of the plant. Plants produce one, or rarely two, flowers per day; the flowers open in mid-morning and wither soon after noon. Flowers do not produce nectar, but attract pollinators – primarily bees and flies, but also weevils and skippers – with pollen rewards. During the bud stage, flowers are frequently visited by a species of bee (Lasioglossum zephyrum) that has learned to open the buds and remove pollen from the early ripening anthers, ensuring that it has first and possibly exclusive access to that flower’s pollen. Plants are reported to produce abundant seed, and seeds will readily germinate if exposed to full light in the warm temperatures of late spring and early summer. Xyris tennesseensis flowers that are cross-pollinated have the greatest seed set but bagged flowers also produce relatively large numbers of seed, indicating that pollinators are not necessary for reproduction. In greenhouse studies, self-pollinated flowers produce seeds with higher rates of germination.
Surveys are best conducted during flowering (August–September) and when flowers are open, mid- to late-morning.
Georgia, Alabama, and Tennessee.
Road construction, quarrying, logging and clearcutting, soil disturbances, cattle trampling and grazing, exotic pest plants, draining and filling wetlands, stream impoundment, off-road vehicle use, and lowering of the water table by groundwater pumping.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Human intrusions & disturbance | Natural system modifications | Agriculture & aquaculture |
| Specific Threat | None | None | None |
Xyris tennesseensis is ranked S1 by the Georgia Department of Natural Resources, indicating that the species is critically imperiled in Georgia. It is listed as Endangered by the State of Georgia and the U.S. Fish and Wildlife Service. Fifteen populations are documented in Georgia, one on state conservation land and 2 on environmentally managed highway rights-of-way. Seven populations have been confirmed since 2000.
Protect sites from mechanical disturbances such as road construction, quarrying, and mechanical clearing and from trampling and grazing by cattle. Eradicate exotic pest plants. Avoid draining or filling wetlands. Restore water table to historic levels by reducing groundwater pumping. Purchase or protect sites with conservation easements.
Baskin, C.C. and J.M. Baskin. 2003. Seed germination and propagation of Xyris tennesseensis, a federal endangered wetland species. Wetlands 23(1): 116-124. https://link.springer.com/article/10.1672/0277-5212(2003)023[0116:SGAPOX]2.0.CO;2
Boyd, R.S., A. Teem, and M.A. Wall. 2011. Floral biology of an Alabama population of the federally endangered plant, Xyris tennesseensis Kral (Xyridaceae). Castanea 76(3): 255-265. https://bioone.org/journals/Castanea/volume-76/issue-3/11-006.1/Floral-Biology-of-an-Alabama-Population-of-the-Federally-Endangered/10.2179/11-006.1.full
Boyd, R.S. and J.M. Moffett. 2003. Management of Xyris tennesseensis (Tennessee Yellow-eyed Grass), a federally endangered plant species. Georgia Department of Transportation. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.484.1025&rep=rep1&type=pdf
Boyd, R.S., J.M. Moffett, M.A. Wall, A. Teem, J. Cochrane, R. Cody, and T.W. Barger. 2000. Status, ecology and management concerns of the Tennessee yellow-eyed grass (Xyris tennesseensis Kral). U.S. Fish and Wildlife Service, Jackson, Mississippi.
Chafin, L.G. 2007. Field guide to the rare plants of Georgia. State Botanical Garden of Georgia and University of Georgia Press, Athens.
GADNR. 2020. Element occurrence records for Xyris tennesseensis. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle, Georgia.
Johnson, T., J.M. Cruse-Sanders, and G.S.Pullman. 2012. Micropropagation and seed cryo-preservation of the critically endangered species Tennessee Yellow-eyed Grass, Xyris tennesseensis Kral. https://link.springer.com/content/pdf/10.1007/s11627-011-9420-1.pdf
Kral, R. 2000. Xyris tennesseensis species account. Flora of North America, Vol. 22. Oxford University Press, New York. http://beta.floranorthamerica.org/Xyris_tennesseensis
Kral, R. 1978. A new species of Xyris (Sect. Xyris) from Tennessee and northwestern Georgia. Rhodora 80(823): 444-447. https://www.jstor.org/stable/23311161?seq=1#metadata_info_tab_contents
Kral, R. 1983. A report on some rare, threatened, or endangered forest-related vascular plants of the South. Technical Publication R8-TP2. United States Forest Service, Atlanta.
Moffett, J.M. 2008. Xyris tennesseensis: status survey, habitat restoration/management concerns, and relation to a new xyrid, Xyris spathifolia. Auburn University, ProQuest Dissertations Publishing. https://search.proquest.com/docview/304688956?pq-origsite=gscholar&fromopenview=true
Moffett, J.M., Jr. and R.S. Boyd. 2013. Management of a population of the federally endangered Xyris tennesseensis (TennesseeYellow-Eyed Grass). Castanea 78(3): 198-212. https://www.jstor.org/stable/24619734?seq=1#metadata_info_tab_contents
NatureServe. 2020. Xyris tennesseensis species account. NatureServe Explorer. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.148370/Xyris_tennesseensis
Patrick, T.S., J.R. Allison, and G.A. Krakow. 1995. Protected plants of Georgia. Georgia Department of Natural Resources, Natural Heritage Program, Social Circle.
USFWS. 2019. Tennessee Yellow-eyed Grass (Xyris tennesseensis) species profile and related documents. U.S. Fish and Wildlife Service, Washington D.C. https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=Q2MP
Wall, M.A., A.P. Teem, and R.S. Boyd. 2002. Floral manipulation by Lasioglossum zephyrum (Hymenoptera: Halictidae) ensures first access to floral rewards by initiating premature anthesis of Xyris tennesseensis (Xyridaceae) flowers. Florida Entomologist 85(1): 290-291.
Weakley, A.S. 2015. Flora of the southern and mid-Atlantic States. University of North Carolina Herbarium, University of North Carolina, Chapel Hill. http://www.herbarium.unc.edu/flora.htm
Linda G. Chafin
L.Chafin, Nov. 2008: original account.
D.Weiler, Jan. 2010: added pictures.
L. Chafin, June 2020: updated original account.
