|Photo was taken by Gil Nelson|
|Division:||Magnoliophyta – Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
| Seymeria cassioides|
(J.F. Gmel.) S.F. Blake
|Natural range of Seymeria cassioides from USDA NRCS Plants Database.|
Common names: Yaupon blacksenna or Senna seymeria (Nelson 2005).
Synonym: Afzelia cassioides J.F. Gmelin
It is an annual, herbaceous root parasite on several species of southern pine but produces most of its own food.   It can grow about one meter tall and is covered in glandular hairs. Flowers are bright yellow with brown marks near the ovary and have a small pore anther opening instead of a long slit.  "Erect, often profusely branched, presumably parasitic, glandular-pubescent annuals. Leaves opposite, pinnately or bipinnately parted or divided into linear to filiform segments. Flowers axillary, solitary, the terminal racemes weakly differentiated. Calyx lobes 5, longer than the tube; corolla yellow, rotate, 9-10 mm long, nearly regular, the lobes 5, longer than the tube; stamens 4, exserted, filaments pubescent. Capsule ovoid, 4-6 mm long; seeds numerous, winged." "Plant profusely branched, the branches ascending, stem pubescence short, antrorse. Leaves mostly less than 1 cm long, segments filiform, less than 0.5 mm wide. Calyx lobes linear, 1.5-2.5 mm long. Capsule glabrous."
In the Coastal Plain region, S. cassioides can be found in wet to mesic pine flatwoods, wet savannas, seepage slopes, and ectones between pine flatwoods and cypress/titi swamps.   It has been recorded to grow in loamy sand, red clay and poorly drained areas.  It is one of the most serious native parasites.  Associated species include Pinus, Cypress, and Cyrilla. 
This species is thought to be dispersed by wind.
Seed bank and germination
It often reproduces profusely after fire because it has the ability to reproduce quickly on open ground.  Thus, the best way to control S. cassioides may be to implement a prescribed burn after seeds germinate in the spring, but before flowers appear. 
Conservation and management
Cultivation and restoration
Plantations appear to be at a higher risk of high Seymeria populations than natural stands because of the greater area of exposed soil in the early years of establishment and the frequent use of fuel reduction burns. 
References and notes
- Crow, A. B. and C. L. Shilling. 1980. Use of prescribed burning to enhance southern pine timber production. Southern Journal of Applied Forestry 4:15-18.
- Fitzgerald, C. H., R. C. Schultz, J. C. Fortson and S. Terrell. 1977. Effects of Seymeria cassioides infestation on pine seedling and sapling growth. Southern Journal of Applied Forestry 1:26-30.
- Musselman, Lytton J., and William F. Mann, Jr. "Root Parasites of Southern Forests." Southern Forest Experiment Station (1978).
- 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. 956. Print.
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: July 2015. Collectors: Loran C. Anderson, Wilson Baker, R. Komarek, Leon Neel, T. MacClendon, Boothes, Robert K. Godfrey. States and Counties: Florida: Franklin, Jackson, Liberty, Wakulla. Georgia: Thomas. Compiled by Tall Timbers Research Station and Land Conservancy.
- Kral 1983, USFWS 1992.
- Musselman, Lytton J. "Parasitic Weeds in the Southern United States."Castanea 61.3 (1996): 271-92. Web.
- Nelson, Gil. East Gulf Coastal Plain. a Field Guide to the Wildflowers of the East Gulf Coastal Plain, including Southwest Georgia, Northwest Florida, Southern Alabama, Southern Mississippi, and Parts of Southeastern Louisiana. Guilford, CT: Falcon, 2005. 196. Print.
- Kirkman, L. Katherine. Unpublished database of seed dispersal mode of plants found in Coastal Plain longleaf pine-grasslands of the Jones Ecological Research Center, Georgia.
- Stangle, Charles M., Lytton J. Musselman. (1961). "Some growth aspects of Seymeria cassioicies". Forest Service - Southern Forest Experiment Station - Research Note. USDA. SO-276:1-3.
- Wade, D. D. 1978. Seymeria infestation and prescribed burns. Southern Journal of Applied Forestry 2:20148-4419.
- Grelen, H. E. and W. F. Mann. 1973. Distribution of Senna seymeria (Seymeria cassioides) a root parasite on southern pines. Economic Botany 27:339-342.