|Photo taken by Gil Nelson|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
|Family:||Clusiaceae ⁄ Guttiferae|
(Torr. & A. Gray) A. Gray ex S. Watson
|Natural range of Hypericum microsepalum from USDA NRCS Plants Database.|
Common name: Flatwoods St. Johnswort
Synonyms: Crookea microsepala (Torr. & A. Gray) Small
Hypericum microsepalum is an evergreen, arborescent plant that occurs along coastal ecoclines of the Florida panhandle (nomenclature follows Godfrey 1988).
“Usually glabrous herbs or shrubs. Leaves usually punctate, simple, opposite, entire, usually sessile or subsessile, exstipulate. Inflorescence basically cymose; flowers perfect, regular, bracteates, subsessile or short-pedicellate, sepals 2, 4, or 5, persistent; petals 4 or 5, usually marcescent, yellow or pink; stamens 5-numerous, separate or connate basally forming 3-5 clusters or fascicles, filaments usually persistent; carpels 2-5, stigmas and styles separate or fused, ovary superior, 1-locular or partly or wholly 2-5 locular, placentation axile or parietal. Capsules basically ovoid, longitudinally dehiscent, styles usually persistent; seeds numerous, lustrous, areolate, cylindric, or oblong. In general, our species form a polymorphic complex with many intergrading taxa.”
This plant occurs from southern Georgia to the Florida Panhandle.
Hypericum microsepalum and H. brachyphyllum are both shrubby in habit, producing multiple shoots from the base whereas H. chapmanii produces a single stem with thick, flaky bark. Hypericum microsepalum has a high survival rate when transplanted in lowland areas however the populations quickly decline in the absence of fire.
Hypericum microsepalum is associated with dry upland pine savannas where there is a 2–3 year fire frequency. It also frequent moist to wet pine flatwoods. This species is one of the most abundant seepage savanna shrubs that resprouts from the root crowns.
It generally occurs in sandy soil, and in addition to the native habitat types as mentioned above, it can be found in some disturbed habitats such as roadsides.
Associated species includes Cyrilla parvifolia, Vaccinium darrowi, V. myrsinites, Ilex glabra, Polygala lutea, P. nana, Xyris brevifolia, Lyonia mariana, Myrica cerifera, Gaylussacia nana, Lobelia paludosa, Salix caroliniana Hypericum galioides, Myrica, Vaccinium, Aristida stricta, Ilex glabra, Pinus palustris, and Serenoa repens.
H. microsepalum has been observed flowering January through July, and in November and December with peak inflorescence in March. Fruiting has been observed in January through May, as well as in July.
All species produce perfect flowers and the dehiscent, septicidal capsules contain numerous seeds. Seeds are dispersed by gravity and occasionally by birds.
Seed bank and germination
All species have life spans of approximately 10 years and persistent seed banks.
Different fire seasons influence the growth of Hypericum microsepalum as recorded by Drewa (2006). Stem densities were greater after dormant-season fires than growing-season fires. When compared to initial levels, H. microspealum grew to densities that were 7x greater after multiple dormant-season fires. Overall, densities were greater after repeated dormant-season fires than growing-season fires, though the difference was not significant.
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. 709. Print.
- Crandall, R. M. and W. J. Platt (2012). "Habitat and fire heterogeneity explain the co-occurrence of congeneric resprouter and reseeder Hypericum spp. along a Florida pine savanna ecoline." Plant Ecology 213: 1643-1654.
- Drewa, P. B., J. M. Thaxton, et al. (2006). "Responses of root-crown bearing shrubs to differences in fire regimes in Pinus palustris (Longleaf pine) savannas: exploring old-growth questions in second-growth systems." Applied Vegetation Science 9: 27-36.
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: John Jensen, Carl Noedman, Preston Adams, Robert K. Godfrey. Sidney McDaniel, Mark A Garland, Preston Adams, Walter S. Judd, Kent D. Perkins, Scott Zona, Loran C. Anderson, William P. Adams, Robert Kral, H. E. Grelen, M. Knott, L. B. Trott, Steve L. Orzell, M. Davis, K. M. Meyer, and A. Townesmith. States and Counties: Florida: Bay, Calhoun, Dixie, Franklin, Gulf, Jackson, Jefferson, Lafayette, Liberty, Madison, Marianna, Okaloosa, Santa Rosa, Taylor, Wakulla, and Walton. Georgia: Thomas.
- Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. www.gilnelson.com/PanFlora/ Accessed: 12 DEC 2016
- Drewa, P., W. Platt, et al. (2002). "Community Structure along Elevation Gradients in Headwater Regions of Longleaf Pine Savannas." Plant Ecology 160(1): 61-78.