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Tracy's Dew-threads, Drosera tracyi, by Hugh and Carol Nourse. Image may be subject to copyright.
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Drosera tracyi Macfarlane

Tracy's Dew-threads

Federal Protection: No US federal protection

State Protection: No Georgia state protection

Global Rank: G3G4

State Rank: S1

Element Locations Tracked in Biotics: Yes

SWAP High Priority Species (SGCN): No

Element Occurrences (EOs) in Georgia: 13

Habitat Summary for element in Georgia: Pitcherplant bogs; grassy seepage slopes


Description

Perennial carnivorous herb with leaves and flower stalks arising in clumps. The leaves are 12-20 inches (30-50 cm) tall and very narrow (1-2 mm), erect, pale green with red bases, and covered with glistening, colorless glands. Elongated flower clusters unfurl at the top of green, hairless stalks that are 10-24 inches (25-60 cm) tall. Flowers are 1-1.5 inches (2.4-4 cm) wide, with 5 oval, rose-pink petals (rarely white); the short flower stalks are covered with glandular hairs. The fruit is a five-segmented capsule bearing numerous black seeds.

Similar Species

Thread-leaf Sundew (Drosera filiformis) is a smaller version of Tracy’s Dew-threads. Its leaves are 3-12 inches (8-30 cm) long and less than 1 mm wide. The glandular hairs on the leaves are red to purple. The stalk supporting the flower cluster is about 2.5 - 10 inches (6-26 cm) long; the flowers are 0.5-1 inch (1.4-2.4 cm) wide. In the south, it is known from Florida and North Carolina, and several states further north; it is imperiled throughout its range.

Related Rare Species

Roundleaf Sundew (Drosera rotundifolia) occurs in mountain bogs in three northeast Georgia counties. Its spoon-shaped leaves are held in rosettes close to the ground. For more information, see: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200009769

Habitat

Tracy's Dew-threads occurs in wet savannas, pitcherplant bogs, and sunny, open seepage herb bogs in Georgia’s Coastal Plain.

Life History

All North American species of Drosera form hibernacula at the soil surface; these are tightly packed, overwintering clusters of leaf buds that are protected from the elements by a dense mat of hairs. In the spring, the buds begin to elongate and uncoil into erect leaves, similar to the way fern leaves unfurl.

The leaves of Tracy’s Dew-threads are covered with glands that exude a sticky mucilage. The glands around the margins of the leaves have stalks, the glands toward the center of the leaf have shorter stalks, and those in the very center are sessile. Insects are drawn to the leaves by the glistening glands. Once they land, their presence triggers a plant hormone that prompts the leaf to fold inward along the midvein and stimulates the long-stalked marginal glands to fold over the prey. The insects then become covered in mucilage and suffocate. The long-stalked glands produce digestive enzymes as well as mucilage, and the insect is soon digested; the nutrients are absorbed by the surface of the leaf.

The flowers open one by one, from the bottom of a coiled inflorescence up, with unopened buds at the top. Flowers begin to open about 9:00 am and close about five hours later; some flowers persist for two days. They are probably pollinated by bees and are also capable of self-pollination.

Survey Recommendations

Surveys may be conducted throughout the growing season; there are only two Drosera species in the southeast with erect, linear leaves, and they can be distinguished by the colors of the leaf glands.

Range

Drosera tracyi occurs in the Coastal Plain of southwestern Georgia, Florida, Alabama, Mississippi, and formerly southeastern Louisiana (it is possibly extirpated).

Threats

Drosera filiformis habitat – wet savannas and seepage bogs – is one of the most threatened habitats in Georgia. These wetlands have been ditched, drained, and filled in order to convert them to pine plantations, pastures, and residential and commercial developments. Where intact, they are often degraded by fire suppression and subsequent woody plant encroachment. Pitcherplant bogs are heavily impacted by feral hog rooting. Drosera tracyi depends on full sun and permanently saturated soils.

Georgia Conservation Status

Drosera tracyi is currently known from only one site in Georgia, where it grows in abundance on an ecologically managed quail plantation. Historically, it was known from another 12 bogs, several of which may still be intact. Further survey work is warranted.

Conservation Management Recommendations

Protect habitat from ditching, draining, and conversion to pine plantations, pasture, and development. Apply prescribed fire in the growing season every 2-3 years. Control feral hogs. Survey known historical sites as well as other southwest Georgia bogs for this species.

References

Mellichamp, T.L. 2015. Drosera tracyi species account. Flora of North America, Volume 6. Oxford University Press, New York. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250101269

GADNR. 2019. Element occurrence records for Drosera tracyi. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle.

Godfrey, R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of southeastern United States. University of Georgia Press, Athens.

NatureServe. 2019. Drosera tracyi species profile. NatureServe Explorer: An online encyclopedia of life, Version 7.1. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.137057/Drosera_tracyi

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

Authors of Account

Linda G. Chafin

Date Compiled or Updated

L. Chafin, 20 May 2019: Original account

Tracy's Dew-threads, Drosera tracyi, by Eleanor Dietrich. Image may be subject to copyright.