Mecardonia acuminata

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Mecardonia acuminata
Meca acum.jpg
Photo by John R. Gwaltney, Southeastern
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida – Dicotyledons
Order: Scrophulariales
Family: Scrophulariaceae
Genus: Mecardonia
Species: M. acuminata
Binomial name
Mecardonia acuminata
(Walter) Small
MECA ACUM dist.jpg
Natural range of Mecardonia acuminata from USDA NRCS Plants Database.

Common name: mecardonia, common axil-flower, pond axil-flower, Florida axil-flower[1]

Taxonomic notes

Synonyms: Pagesia acuminata (Walter) Pennell ssp. typica; Mecardonia acuminata ssp. acuminata; Mecardonia acuminata ssp. microphyla (misspelling); Pagesia acuminata (Walter) Pennell ssp. microphylla (Rafinesque) Pennell; Mecardonia acuminata ssp. peninsularis (Pennell); Pagesia acuminata (Walter) Pennell ssp. peninsularis (Pennell) Pennell[1]

Varieties: Mecardonia acuminata (Walter) Small var. acuminata; Mecardonia acuminata (Walter) Small var. microphylla (Rafinesque) Pennell; Mecardonia acuminata (Walter) Small var. peninsularis Pennell[1]


It has been observed to be both frequent and infrequent where it is found.[2]

"Erect, branched, glabrous perennial, the stems angled, 1-5 dm tall, usually blackening on drying. Leaves opposite, firm, oblanceolate to elliptic, mostly 1-4.5 cm long, 5-12 mm wide, distally serrate, sessile or narrowly cuneate to a short, obscure petiole. Peduncles axillary, solitary, about as long, or longer than the subtending leaf, with 2 linear bractlets at the base; sepals 5, linear-lanceolate, 7-9 mm long; corolla white or tinged with lavender, personate, 9-11 mm long; fertile anthers 4, normal. Capsule ellipsoid, 6-8 mm long."[3]

Var. microphylla is distinguished by its peduncles, which are smaller than 10 mm and its sepals, which are wider than 2 mm. Both var. peninsularis and var. acuminata exhibit the reverse of this. Var. peninsularis has main stem leaves that are 1.2-2 cm long, outer sepals that are 5-6 mm long, a corolla that is 7-9 mm long, a strongly branched base, and widely-spread branches. On the other hand, var. acuminata has main stem leaves that are 3-4.5 cm long, outer sepals that are 6-8 mm long, a corolla that is 9-10 mm long, branching that begins above the base, and a usually erect growth.[1]


Var. acuminata ranges from Deleware and Maryland, south to north peninsular Florida, west to east Texas, and north to Kentucky, Tennessee, and Missouri. Var. microphylla ranges from southcentral Georgia to the Florida Panhandle and west to eastern Louisiana.[1] Var. peninsularis ranges from the northern Florida peninsula, south to southern Florida.[1]



This species has been found along grassy limestone glades in open areas, in floodplain forests, and savannas.[2] It also can be found in human distrubed areas such as parking areas, powerline corridors, and roadside ditches.[2] This species grows in semi-shaded environments wet, limestone, and sandy loam soils.[2] Var. acuminata and var. peninsularis thrive in wetland habitat types, such as marshes, ditches, wet pine savannas, bottomland forests, wet disturbed areas. Var. microphylla is limited to the margins of Coastal Plain ponds and wet pine savannas.[1] In Louisiana, soils are of the upland coastal plain type with little slope and low fertility.[4] Associated species include Sporobolus vaginiflorus, Stenaria nigricans, Polygala grandiflora var. angustifolia, Rhynchospora, Fuirena, and Scleria.[2]


M. acuminata flowers from July through September and fruits from August through October.[1]

Seed dispersal

This species is thought to be dispersed by gravity.[5]

Fire ecology

Populations of Mecardonia acuminata have been known to persist through repeated annual burns.[6]

Conservation, cultivation, and restoration

Cultural use

Photo Gallery

References and notes

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 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.
  2. 2.0 2.1 2.2 2.3 2.4 Florida State University Robert K. Godfrey Herbarium database. URL: Last accessed: June 2014. Collectors: Loran C. Anderson, Ann F. Johnson, Wilson Baker, Robert K. Godfrey, R.A. Norris, R. Komarek, and Lisa Keppner. States and Counties: Florida: Calhoun, Gadsden, Jackson, Jefferson, Leon, Suwannee, Taylor, and Washington. Georgia: Grady.
  3. 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. 938. Print.
  4. Thill, R. E. (1983). Deer and cattle forage selection on Louisiana pine-hardwood sites. New Orleans, LA, USDA Forest Service.
  5. 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.
  6. Platt, W.J., R. Carter, G. Nelson, W. Baker, S. Hermann, J. Kane, L. Anderson, M. Smith, K. Robertson. 2021. Unpublished species list of Wade Tract old-growth longleaf pine savanna, Thomasville, Georgia.