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Xyris scabrifolia Harper
Roughleaf Yellow-eyed-grass
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G3
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: High Conservation Concern
Element Occurrences (EOs) in Georgia: 10
Habitat Summary for element in Georgia: Sedge bogs; pitcherplant bogs; pine flatwoods
Perennial herb growing singly or in small tufts, the base of the plant resting shallowly on the soil; the leaf bases are overlapping and conspicuously expanded so that the base of the plant appears bulbous. The entire plant is densely covered with tiny, pale bumps, giving it a glazed appearance and a roughened feel. Leaves are 4 - 20 inches (10 - 50 cm) long and less than 0.4 inch (10 mm) wide, in a basal rosette, more or less erect, spirally twisted, green with pinkish, purplish, or dark brown, fleshy bases; short, black scale leaves are often present at the very base of the plant. Flowering stems are 8 - 43 inches tall and up to 0.1 inch wide (20 - 110 cm tall and up to 2.5 mm wide), erect, round in cross-section. Flowering spikes are 0.25 - 0.8 inch (7 - 20 mm) long, held at the top of the stem, cone-like and composed of many tightly overlapping bracts about 0.28 inch (6 - 8 mm) long with entire margins and broadly rounded tips. The bracts are tan with a gray-green patch when immature, becoming reddish brown when mature. Flowers open from midday to mid-afternoon then wither. The three petals are yellow and about 0.2 inch (5 mm) long and wide (narrow petal bases – ‘claws’ – are hidden under the bracts). Sepals are about 0.28 inch (6 - 8 mm) long, pale brown, papery, fringed, and always hidden under the bracts. There are 3 fertile stamens, 3 very hairy sterile stamens, and a single, 3-branched style. The seeds are about 1.0 mm long, translucent (not covered with a white mealy substance), narrowly oval or elliptic, with several longitudinal ribs and fainter cross ribs.
Yellow-eyed Grass species (Xyris spp.) are notoriously similar and hard to key out, but Xyris scabrifolia is relatively easy to recognize in the field. It is distinguished by its “glazed” appearance owing to the dense coating of pale bumps on its stem and leaves; its twisted leaves and flowering stems; fleshy, bulbous leaf bases; short, black scale leaves at the very base of the plant; and round, always yellow, petals.
X. scabrifolia most closely resembles the rare X. chapmanii (Chapman’s Yellow-eyed Grass), see “Related Rare Species” below. Xyris scabrifolia also resembles a common species, Tall Yellow-eyed Grass (Xyris platylepis), which also has twisted stems, bulbous bases resting shallowly in the soil, and short, black scale leaves at the base of the plant. X. platylepis plants are smooth (not glazed or roughened with bumps) or possibly roughened only along leaf margins and stem ridges. Its petal blades are oval, and either white or yellow.
Xyris scabrifolia resembles Xyris chapmanii (Chapman’s Yellow-eyed Grass), which is also very rare in Georgia. X. chapmanii is deeply (rather than shallowly) set in the soil and does not have expanded leaf bases or a bulbous base; it also lacks the short, black scale leaves at the very base of the plant. Its leaves are 2-4 mm wide and do not have the glazed look or rough feel of X. scabrifolia. X. chapmanii petal blades are smaller, about 3 mm long and wide. X. chapmanii occurs in streamhead seepage bogs in deep muck. X. chapmanii is lumped with X. scabrifolia in some treatments (Kral 2000).
Xyris drummondii (Drummond Yellow-eyed Grass) occurs in pine flatwoods in Georgia’s Coastal Plain. For more information, see: https://georgiabiodiversity.org/portal/profile?group=plants&es_id=16101
Xyris tennesseensis (Tennessee Yellow-eyed Grass) is listed as Endangered by both state and federal agencies. It occurs in seepy margins of limestone spring runs in northwest Georgia. For more information, see: https://georgiabiodiversity.org/portal/profile?group=plants&es_id=17987
Sandy-peaty soils of bogs, seepage slopes, sandhill seepage bogs, openings in wet pine flatwoods and savannas.
Harper's Yellow-eyed Grass is a short-lived perennial herb that reproduces sexually by seed as well as vegetatively by bulb-like buds that develop in the axils of leaves, thus often forming clumps of plants, although solitary plants are occasionally seen. Plants produce one, or rarely two, bisexual flowers per day; the flowers open from midday to mid-afternoon then wither soon after. The flowers do not produce nectar, but attract pollen-eating insects such as bees and flies that effect cross-pollination. Although no studies of this species’ breeding system have been published, other Xyris species are able to produce seeds following both cross- and self-pollination.
Robert Kral (1966) conducted greenhouse and field studies and reported that Xyris seeds can germinate on a moist surface within two weeks of maturity, producing small plant rosettes within a month after germination. Most Xyris plants flower within a year after germination. Kral also stated that Xyris seeds can survive long periods of dormancy; he stored dry Xyris seeds at room temperatures for ten years and then successfully germinated them in a greenhouse.
Harper's Yellow-eyed Grass often grows with other Yellow-eyed Grasses, such as X. caroliniana, X. ambigua, X. baldwiniana, and X. drummondii.
Surveys are best conducted during flowering, midday to mid-afternoon, July–September.
Georgia, Florida panhandle, west to east Texas, and north to New Jersey, largely in the Coastal Plain. In Georgia, one population was discovered in the lower Piedmont in 1901, but has not been seen since.
Ditching and draining of bogs and seepage slopes. Conversion of habitat to pine plantations, pastures, agriculture, and developments. Disturbances in upslope pinelands that alter seepage hydrology. Fire suppression and encroachment by woody plants. Digging by feral hogs.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Pollution | Climate change & severe weather | None |
| Specific Threat | None | None | None |
Harper's Yellow-eyed Grass is ranked S1 by the Georgia Department of Natural Resources, indicating that it is critically imperiled in the state. Only four populations have been documented in Georgia and none of these have been confirmed in the last 50 years. None occurred on conservation lands.
Protect flatwoods and savannas from ditching, draining, and other hydrological alterations. Protect seepage slope and bog hydrology from the effects of upland development. Apply prescribed fire every 2-3 years during the growing season, allowing fire to burn into bogs and extinguish naturally. Avoid placing fire breaks along small streams adjacent to seepage slopes or in other areas where they may interfere with seepage hydrology. Eradicate feral hogs.
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
GADNR. 2019. Element occurrence records for Xyris scabrifolia. Georgia Department of Natural Resources, Wildlife Resources Division. Social Circle, Georgia.
Kral, R. 2000. Species account for Xyris scabrifolia. Flora of North America North of Mexico, vol. 22. http://beta.floranorthamerica.org/Xyris_scabrifoliaAccessed 29 December 2019. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=222000477
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States: monocotyledons. University of Georgia Press, Athens.
Kral, R. 1983. A report on some rare, threatened, or endangered forest-related vascular plants of the South. U.S. Dept. of Agriculture Forest Service Technical Publication R8-TP2, Athens, GA.
Kral, R. 1966. Xyris (Xyridaceae) of the continental United States and Canada. Sida 2(3):177-260. https://www.jstor.org/stable/41966284?seq=1#metadata_info_tab_contents
LANHP. Xyris scabrifolia – Harper’s yellow-eyed grass. Rare Plants of Louisiana. Louisiana Natural Heritage Program, Louisiana Department of Wildlife and Fisheries, Baton Rouge, LA. Accessed 29 December 2019. http://www.wlf.louisiana.gov/fact-sheet-rare-plant/xyris-scabrifolia
NatureServe. 2019. Species account for Xyris scabrifolia. NatureServe Explorer. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.151523/Xyris_scabrifolia
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
Linda G. Chafin, 28 December 2019: original account
