Diodia virginiana

Diodia virginiana
Photo taken by Gil
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Magnoliopsida – Dicotyledons
Order:	Rubiales
Family:	Rubiaceae
Genus:	Diodia
Species:	D. virginiana
Binomial name
Diodia virginiana L.
Natural range of Diodia virginiana from USDA NRCS Plants Database.

Common name: Virginia buttonweed

Taxonomic notes

Synonyms: Diodia virginiana var. attenuata Fernald; D. virginiana var. latifolia Torrey & A. Gray; D. virginiana var. virginiana; D. tetragona Walter; D. hirsuta Pursh

Description

Diodia virginiana tends to grow in spreading mats, sometimes floating in shallow water.

Generally, for Diodia genus, they are "annual or perennial herbs. Leaves sessile, opposite pubescent or glabrate, margins hyaline, setose-serrate; stipules linear or fimbriate, ½ as long, or longer than, the fruit. Flowers 4-merous, axillary, usually solitary, sessile; calyx lobes equal or unequal; corolla salverform. Fruit leathery, surmounted by the persistent calyx lobes, splitting into 2, indehiscent, 1-seeded segments."

Specifically, for D. virginiana species, they are "erect or spreading, usually pubescent perennial from a woody root crown, the stems branched, 1-6 dm or more long. Leaves elliptic-lanceolate to oblanecolate, mostly 2-7 cm long, 4-12 mm wide. Calyx lobes 2, linear-lanceolate, 2-4 mm long, pubescent; corolla white, tube filiform, 7-9 mm long, lobes 3-4 mm long, the inner surface pubescent; stigmas filiform or the style appearing cleft. Fruit pubescent, oblong-ellipsoid, 5-9 mm long, 3-5 mm in diam., prominently ridged. Fruit splitting into 2, indehiscent, 1-seeded segments."

Ecology

Habitat

D. virginiana occurs in moist to wet areas, and areas subject to periodic inundation like ephemeral ponds. It occurs in a wide range of light levels, from deep shade to full sun, but tends to prefer sandy soil types such as loamy sand, sand, sandy loam and sandy peat. It can be found in natural communities including pine savannas, grassy areas near lakes and ponds, prairies, floodplain forests, sand bars, cypress-hardwood swamps, swampy woodlands, wetland areas, and calcareous hammocks. However, it can also appear in disturbed habitat, like cutover pine woods, roadsides, old fields, and mowed areas.

Associated species include Diodia teres, Aristida stricta, Polygonum, Sabatia dodecandra, Hypericum galioides, Eupatorium semiserratum.

Phenology

Flowering and fruiting have been observed from May through November.

Seed dispersal

According to Kay Kirkman, a plant ecologist, this species disperses by gravity.

Fire ecology

It is favored by frequent fire, and grows in habitats maintained by fire (FSU Herbarium).

References and notes

Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: Loran C. Anderson, R. K. Godfrey, R. Komarek, R. Kral, Sidney McDaniel, R. A. Norris, A.E. Radford, Cecil R. Slaughter, B. K. Holst, Valerie Renard, Lovette E. Williams, Rev. Robert Brinker, Robert L. Lazor, Grady W. Reinert, Suellen Folensbee, Paul L. Redfearn, Jr., S. W. Leonard, Gary R. Knight, Jame Amoroso, W. G. D'Arcy, Gywnn W. Ramsey, H. Larry Stripling, W. P. Adams, K. Craddock Burks, William Lindsey, D. W. Mather, Jean W. Wooten, Robert J. Lemaire, O. Lakela, Robert J. Lemaire, Leon Neel, R. F. Doren, A. Gholson Jr., K. Willis, R. Cherry, and Annie Schmidt. States and Counties: Florida: Alachua, Bay, Calhoun, Charlotte, Citrus, Collier, Columbia, Dade, Dixie, Duval, Escambia, Flagler, Franklin, Hamilton, Highland, Holmes, Indian River, Jackson, Jefferson, Lake, Leon, Levy, Liberty, Madison, Marion, Okaloosa, Orange, Osceola, Palm Beach, Polk, Osceola, Sarasota, Santa Rosa, St. Johns, Sumter, Taylor, Wakulla, Walton, and Washington. Georgia: Grady and Thomas.