|Photo by Roger Hammer, Atlas of Florida Vascular Plants|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida - Dicotyledons|
|Natural range of Aureolaria virginica from USDA NRCS Plants Database.|
Common names: Downy yellow false foxglove; Downy oak-leech; Virginia oak-leech
Synonyms: Gerardia virginica (Linnaeus) Britton, Sterns, & Poggenburg
Varieties: Aureolaria microcarpa Pennell; Aureolaria virginica (Linnaeus) Pennell
In the genus Aureolaria, the plants are either annual or perennial. They are parasitic on the roots of Quercus (oaks) and turn black when dried. The leaves are opposite or subopposite and branch from the upper portion of the stem (cauline). The flowers are showy, the calyx is 5-parted, the lobes can be shorter or longer than the tube. The flower is yellow in color, bilabiate, and 5-parted. The tube is bell-shaped with spreading lobes. There are 4 stamens, didynamous, and the filaments are flattened with the 2 longer more or less lanose. The anther sacs are basally awned. The stigma is capitate and protruding.
Specifically, A. virginica is a perennial plant that is parasitic to the white oak group. The stems are pubescent, weakly branched or unbranched altogether, and grow to approximately 1 m or more tall. The leaves are lanceolate or ovate-lanceolate, entire or coarsely sinuate to pinnately lobed or parted, somewhat pubescent, and most are 6 - 12 cm long, 1.5 - 4.5 cm wide. The terminal raceme has distinct flowers that are solitary in the axils of opposite bracts. The 6 mm long pedicels are glabrous and most of the time less than 3 mm long at the anthesis. The calyx lobes are lanceolate, equaling or much longer than the tube, approximately 3 - 10 mm long, and is entire. The flower is 3.5 - 4.5 cm long. The capsule is broadly ovoid, 1 - 1.5 mm long, and pubescent. The seeds have several irregular, narrow, hyaline wings.
Listed as critically imperiled in New Hampshire, Vermont and Ontario.
The yellow, flower blooms from May to July; then August to September. This is a polycarpic, hemiparasitic species. It is hemiparasitic because it is autotrophic and able to grow to maturity without attaching to a host. Primary hosts include white oaks, however, Carya and Nyssa are also susceptible. A. virginica attaches to a host through modified roots called haustoria.
Seed bank and germination
Seeds display innate dormancy, which can be broken by exposure of imbibed seeds to appropriate cold stratification conditions. Germination is epigeal with the radical emergence about four days after sowing.
Aureolaria virginica has been observed to host many types of pollinators, including ground-nesting bees from the Andrenidae family such as Andrena hirticincta and Perdita octomaculata, bees from the Apidae family such as Apis mellifera and Bombus impatiens, and plasterer bees from the Colletidae family such as Colletes simulans and C. thysanellae.
Herbivory and toxicology
A. virginica hosts planthoppers such as Pelitropis rotulata (family Tropiduchidae), Stobaera pallida (family Delphacidae), and members of the Acanaloniidae family such as Acanalonia conica and A. servillei, aphids such as Aphis sp. (family Aphididae), fulgoroid planthoppers such as Ormenoides venusta (familty Flatidae), treehoppers such as Micrutalis calva (family Membracidae), and plant bugs such as Lygus lineolaris (family Miridae).
Conservation, cultivation, and restoration
References and notes
- Weakley, A.S. 2020. Flora of the Southeastern United States. Edition of 20 October 2020. University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
- Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 957-8. Print.
- []NatureServe. Accessed: April 1, 2016
- Florida State University Herbarium Database. URL: http://herbarium.bio.fsu.edu. Last accessed: May 2021. Collectors: R. Kral. States and counties: Alabama: Clay. Tennessee: Marion.
- Arizona State University Vascular Plant Herbarium accessed using Southeastern Regional Network of Expertise and Collections (SERNEC) data portal. URL: http://sernecportal.org/portal/collections/index.php Last accessed: May 2021. Collectors: R.S. Freer and D.R. Windler. States and Counties: Maryland: Charles. Virginia: Augusta.
- Louisiana State University, Shirley C. Tucker Herbarium accessed using Southeastern Regional Network of Expertise and Collections (SERNEC) data portal. URL: http://sernecportal.org/portal/collections/index.php Last accessed: May 2021. Collectors: Stephanie M. Gunn-Zumo. States and Counties: Mississippi: Jackson.
- []Lady Bird Johnson Wildflower Center. Accessed: April 1, 2016
- King, B. (1989). Seed Germination Ecology of Aureolaria virginica (L.) Penn. (Scrophulariaceae). Castanea, 54(1), 19-28. Retrieved June 22, 2021, from http://www.jstor.org/stable/4033487
- Discoverlife.org 
- Discoverlife.org