Ageratina aromatica

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Ageratina aromatica
Ageratina aromatica gil.jpg
Photo taken by Gil Nelson
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Order: Asterales
Family: Asteraceae ⁄ Compositae
Genus: Ageratina
Species: A. aromatica
Binomial name
Ageratina aromatica
(L.) Spach
AGER AROM dist.jpg
Natural range of Ageratina aromatica from USDA NRCS Plants Database.

Common names: Lesser snakeroot; Wild hoarhound; Small-leaved White Snakeroot

Taxonomic notes

Synonyms: Eupatorium aromaticum Linnaeus; Eupatorium aromaticum var. aromaticum; Eupatorium aromaticum var. incisum A. Gray; A. aromatica var. aromatica; A. aromatica var. incisa (Gray) C.F. Reed; Eupatorium latidens Small

The genus name Ageratina comes from the Greek word "agera" which means un-aging, not growing old in reference to the longevity of the flowers. The specific epithet comes from the Greek word "aroma" meaning spice seasoning.[1]

Description

A description of Ageratina aromatica is provided in The Flora of North America.

Ageratina aromatica is a perennial.[2] The lifepans of individual plants in the old-growth pine savanna on the Wade Tract, based on multiple years of data from permanent plots, is several years, with genets that become established and flower persisting through 1 - several fires. No plant has been observed to survive more than about 5 years. Ageratina aromatica genets commonly are comprised of a single ramet or a few ramets within a few centimeters of each other, especially after fires have top-killed existing ramets. Underground the roots radiate from the base of the ramet stem and are thickened relative to most fibrous roots. Below ground rhizomes often are not present, but if present are short. [3] It can be distinguished from the closely related A. altissima by having smaller, thicker, and less sharply toothed leaves on shorter petioles, smaller stature, smaller flower heads, and thicker roots, and shorter, firmer pubescence.[4]

Distribution

It is infrequent in west Florida. It is found west to Mississippi, east towards Pennsylvania and Massachusetts.[2] It is regionally rare in New England. In Massachusetts and Connecticut it is listed as endangered (S1) and in Rhode Island is historical only (SH).[4]

Ecology

Habitat

Habitats of A. aromatica include longleaf pine-wiregrass flatwoods and open longleaf pine-scrub-oak-wiregrass savannas, mixed pine-hardwood forests, open oak woods, live oak woodlands, longleaf pine sand ridges, upland woodlands, and rolling red hills. On the Wade Tract, it occurs in open pine savanna along mid and lower mesic slopes,but tends to be absent from drier, sandy ridges. It often occurs in slightly disturbed areas of the Wade Tract.[3] It can also be found in disturbed habitat such as roadsides, along fences, and on the edges of fields.[5] A. aromatica is considered a dominant plant species in post-agricultural longleaf pine savannas.[6] This species is observed in a range of light conditions, from open forest situations to semi-shaded and shady areas. It occurs most frequently in moist sandy loam, dry sand, and areas of lime rock.[5] When exposed to soil disturbance by military training in West Georgia, A. aromatica responds negatively by way of absence.[7]

Associated species: Andropogon, Chamaecrista fasiculata, Eupatorium album, Helianthus angustifolius, Liatris graminifolia, Solidago odora, Sorghastrum nutans, Quercus species, Pinus palustris, Aristida beyrichiana, Quercus laevis, Pinus echinata, Liatris, Dicerandra, and others.[5]

Phenology

It can spread vegetatively in a limited area, but it is dependent on sexual reproduction to colonize new areas.[4] Flowering occurs in the fall[8], and has been observed flowering in the months of October, November, and January with peak inflorescence in October. [9] It has been observed fruiting in October and November as well.[5] On the Wade Tract, flowering occurs at the end of the growing season, in the latter part of October and November. At this time, A. aromatica often is the most abundant and conspicuous flowering composite in the ground layer. The white flowers are at "canopy" height and form flat platforms of inflorescences visited by numerous bees andother flying insects. Flowering may occur sporadically in years between fires, but is most noticeable as highly synchronized flowering displays across mesic landscapes on the Wade Tract following spring fires. [3]

In north Florida, it has been observe to reproduce with A. juncunda suggesting these species are possibly conspecific.[10]

Seed dispersal and germination

This species is thought to be dispersed by wind. [11]

On the Wade Tract, achenes are wind-dispersed in the late fall/early winter. The achenes are light, but the small pappus results in seeds that tend to fall within the vicinity of the parent plant. Germination occurs in the late spring, early summer and seedlings sometime numerous around established plants. Survival of seedlings is very low, but the seedlings appear to be shade tolerant and can persist under the shade of other ground-layer plants. Seedlings in plots on the Wade Tract have reached a size such that they flower within 2-3 years. but many juvenile plants survive for several years before being killed in fires without ever flowering. Cite error: Closing </ref> missing for <ref> tag This species requires full to partial sun, therefore forest maturation and canopy closure resulting from a lack of disturbance such as fire can shade out A. aromatica.[4]

Conservation and management

In New England, it is threatened by fire suppression and lack of disturbance that allows for canopy closure and forest maturation, resulting in lack of sunlight needed for A. aromatica to prosper.[4] It is listed as endangered in the state of Massachusetts. [12]

Cultivation and restoration

Photo Gallery

References and notes

  1. [[1]]Alabama Plants. Accessed: March 22, 2016
  2. 2.0 2.1 Hall, David W. Illustrated Plants of Florida and the Coastal Plain: based on the collections of Leland and Lucy Baltzell. 1993. A Maupin House Book. Gainesville. 100. Print.
  3. 3.0 3.1 3.2 William J. Platt, Unpublished data from ongoing long-term study of ground layer vegetation on the Wade Tract
  4. 4.0 4.1 4.2 4.3 4.4 [[2]]New England Wild. Accessed: March 22, 2016
  5. 5.0 5.1 5.2 5.3 .Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: Loran C. Anderson, Robert Blaisdell, Andre F. Clewell, William B. Fox, J. P. Gillespie, Robert K. Godfrey, C. Jackson, Gary R. Knight, R. Komarek, Robert Kral, Robert L. Lazor, Sidney McDaniel, Richard S. Mitchell, P. L. Redfearn Jr., V. I. Sullivan, Jean W. Wooten, and Geo. Wilder MacClendons. States and Counties: Florida: Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf, Holmes, Jackson, Jefferson, Leon, Levy, Liberty, Madison, Okaloosa, Putnam, Santa Rosa, St. Johns, and Wakulla. Georgia: Grady.
  6. Ostertag, T. E. and K. M. Robertson (2007). A comparison of native versus old-field vegetation in upland pinelands managed with frequent fire, south Georgia, USA. Proceedings of the 23rd Tall Timbers Fire Ecology Conference: Fire in Grassland and Shrubland Ecosystems, Tallahassee, Tall Timbers Research Station.
  7. Dale, V.H., S.C. Beyeler, and B. Jackson. (2002). Understory vegetation indicators of anthropogenic disturbance in longleaf pine forests at Fort Benning, Georgia, USA. Ecological Indicators 1(3):155-170.
  8. Wunderlin, Richard P. and Bruce F. Hansen. Guide to the Vascular Plants of Florida. Second edition. 2003. University Press of Florida: Gainesville/Tallahassee/Tampa/Boca Raton/Pensacola/Orlando/Miami/Jacksonville/Ft. Myers. 295. Print.
  9. 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: 4 MAR 2019
  10. Clewell, A. F. and J. W. Wooten (1971). "A Revision of Ageratina (Compositae: Eupatorieae) from Eastern North America." Brittonia 23(2): 123-143.
  11. 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.
  12. USDA Plants Database URL: https://plants.usda.gov/core/profile?symbol=ANGE