|Photo by John R. Gwaltney, Southeastern Flora.com|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
| Oldenlandia corymbosa|
|Natural range of Oldenlandia corymbosa from USDA NRCS Plants Database.|
Common names: Flat-top mille graines; Diamond-flower
Synonym: Hedyotis corymbosa (Linnaeus) Lamarck
"Diffuse annuals or perennials with opposite, sessile or subsessile leaves connected by fimbriate stipules. Flowers axillary or in few-flowered cymes; calyx lobes 4; corolla white, rotate, minute, shorter than the calyx; stamens 4. Capsule enclosed in the calyx, the apex splitting to release the numerous, minute seeds." 
"Slender, branched, spreading, glabrous annual with erect or decumbent stems 2-5 dm long. Leaves elliptic to linear-elliptic, the largest 1.5-2.5 cm long, 4-7 mm wide. Flower axillary, peduncles filiform, 5-10 mm long, pedicels filiform, 3-5 mm long; calyx glabrous, 1-1.5 mm long, lobes minute, subulate. Seeds brown, angled, ca. 0.2 mm long or broad." 
Oldenlandia corymbosa has been found growing on exposed sandbars in rivers, sidewalk gravel, cracks of concrete, and loamy sand of an open planted peanut field.  Soil types include loamy sand, sandy loam, sandy alluvium, and clayey sand. 
Flowers and fruits August through October. 
The following Hymenoptera families and species were observed visiting flowers of Oldenlandia corymbosa at Archbold Biological Station: 
Halictidae: Lasioglossum lepidii, L. placidensis, L. puteulanum
Sphecidae: Cerceris blakei, C. tolteca
Conservation and management
Cultivation and restoration
Flowers of Oldenlandia corymbosa
Photo by John R. Gwaltney, Southeastern Flora.com
References and notes
- 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. 981. Print.
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: October 2015. Collectors: Loran C. Anderson, R.K. Godfrey, Sidney McDaniel, Annie Schmidt. States and Counties: Florida: Calhoun, Franklin, Gadsden, Gulf, Jackson, Lafayette, Leon, Liberty, Suwannee. Countries: Costa Rica, Panama. Compiled by Tall Timbers Research Station and Land Conservancy.
- Deyrup, M.A. and N.D. 2015. Database of observations of Hymenoptera visitations to flowers of plants on Archbold Biological Station, Florida, USA.