The following Participating Institutions are custodians for this species in the CPC National Collection:
Cincinnati Zoo & Botanical Garden
Cincinnati Zoo & Botanical Garden
The conservation of Xyris tennesseensis is fully sponsored.
Linda G. Chafin contributed to this Plant Profile.
Tennessee yellow-eyed grass (Xyris tennesseensis) is a perennial herb with a fleshy, bulbous base, usually occurring in small clumps. Leaves are 5 - 18 inches (14 - 45 cm) long, - ⅜ inch (0.5 - 1 cm) wide, erect, flat or slightly twisted with swollen, pink or purple leaf bases overlapping up to one-third the length of the blade. The flower stalk is 12 - 28 inches (30 - 70 cm) tall, straight, 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 stalk. A single, cone-like flower spike, ⅜ - ⅝ 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; spikes usually produce only 1 flower per day, which emerges from beneath the rounded tip of a bract. The flower has 3 oblong, yellow petals; sepals do not show above the tip of the bract. Tennessee yellow-eyed grass often occurs with two similar Xyris species. Carolina yellow-eyed grass (X. 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 inch (0.5 cm) wide, twisted, with strongly raised veins.
Distribution & Occurrence
Sunny, permanent wetlands over calcareous bedrock.
Alabama - sand and gravel bars along small to medium sized streams over dolomite and wet seeps.
Georgia - spring runs, edges of shallow streams and ponds, seeps, wet meadows, and swales. Tennessee - small calcareous fens on slopes adjacent to headwater streams.
|Approximately 25 populations are known: 10 in Alabama, 9 in Georgia, 6 in Tennessee.|
Conservation, Ecology & Research
Plants are reported to produce abundant seed (Kral 1990), and Baskin and Baskin (2003) found that 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 produced relatively large numbers of seed, indicating that pollinators are not necessary for reproduction. Self-pollinated flowers produce seeds with higher rates of germination (Boyd et al. 2000).
Patterns of herbivory, seed predation, and seed dispersal are unknown.
use of herbicides in roadside vegetation management
logging and clearcutting
exotic pest plants
draining and filling habitat for conversion to agriculture or residential development
Baskin and Baskin (2003) studied seed dormancy and germination requirements of Tennessee yellow-eyed grass. They concluded that: (1) seeds do not require a dormancy-breaking treatment (cold stratification) in order to germinate in late springsummer, implying that under natural conditions seeds would not germinate until warm, summer temperatures were reached; (2) seeds require light to germinate; (3) seeds will germinate under flooded conditions if light is not limited but do not require inundation; and (4) this species forms a small, short-lived (up to 4 years) seed bank which may be stimulated by removing leaf litter and disturbing the soil to a shallow depth. Conditions for growth and establishment of seedlings were less clear, with plants grown in non-native soil failing to thrive. Plants grown in pots of native soil thrived and flowered the summer following germination. The authors recommend that seeds be sown in situ in late spring or summer (when soil moisture levels are high), in full sun, on the surface of undisturbed organic soil from which litter has been removed.
Boyd et al. (2000) found that Xyris tennesseensis flowers that were cross-pollinated had the greatest seed set but that self-pollinated flowers produced seeds with higher rates of germination.
Other current recommendations include: protect sites from disturbances such as road construction, quarrying, and mechanical clearing; eradicate exotic pest plants; avoid draining or filling wetlands; restore water table to historic levels by reducing groundwater pumping; and use hand-clearing to remove competing shrubs and herbs (Chafin 2007).
Identify secure reintroduction sites
Conduct range-wide survey for new populations
Research effects of loss of genetic diversity and potential levels of inbreeding depression
Research seed banking and seedling recruitment
Conduct cattle exclosure studies
Bring species into national collection.
Conduct controlled reintroduction trials.
Chafin, L.G. 2007. Field guide to the rare plants of Georgia. Athens, Georgia. State Botanical Garden of Georgia and University of Georgia Press. 526p.
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, Georgia. United States Forest Service. 1305p.
Kral, R. 2000. Flora of North America. Vol. 22, Magnoliophyta: Alismatidae, Arecidae, Commelinidae (in part), and Zingiberidae. New York. Oxford University Press. 352p.