Baccharis halimifolia

Baccharis halimifolia
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Genus: Baccharis
Species: B. halimifolia
Binomial name
Baccharis halimifolia
L.
Natural range of Baccharis halimifolia

Baccharis halimifolia is a fall-flowering deciduous or evergreen shrub commonly found in wetlands on the Atlantic and Gulf coastal plains of the eastern United States from Texas and Florida northward to Massachusetts,[1] inland to the District of Columbia[2] and Pennsylvania.[3] The species is also occurs in Mexico,[1] the West Indies,[1] and southernmost Nova Scotia in Canada.[4]

Widely used common names include Eastern Baccharis, Groundsel Bush, Sea Myrtle, and Saltbush, with Consumption Weed, Cotton-seed Tree, Groundsel Tree, Menguilié, and Silverling also used more locally. In most of its range, where no other species of the genus occur, this plant is often simply called Baccharis.

Classification

Flowering Baccharis halimifolia in late autumn in central North Carolina

Baccharis halimifola was first described and named by Carl Linnaeus in his Species Plantarum, published in 1753. No subspecies or varieties are recognized within the species.

This species is the northernmost member of the large Western Hemisphere genus Baccharis in the aster family (Asteraceae).

Senecio arborescens, a Neotropical species, was confused with Baccharis halimifolia in the past.

Description

Late fall flowerheads, with purple sheath around silky white pappus
Carl Linnaeus, who first named and described Baccharis halimifolia (1775 portrait by Alexander Roslin)

Baccharis halimifolia is a shrub growing to about 12 ft (4 m) high and comparably wide, or occasionally a small tree. Its simple, alternate, thick, egg-shaped to rhombic leaves mostly have coarse teeth, with the uppermost leaves entire. These fall-flowering Baccharis plants are dioecious, with male and female flowers on separate individuals. Their flowers are borne in numerous small, compact heads in large leafy terminal inflorescences, with the snowy-white, cotton-like female flower-heads showy and conspicuous at a distance.[5][6]

The species is sometimes confused with the marsh-elder (Iva frutescens),[7] with which it often co-occurs, but the Baccharis has its leaves alternate, while those of the Iva are opposite.[5]

Ecology

Baccharis halimifolia, usually found in wetlands, is unusually salt-tolerant, and often found along salty or brackish shores of marshes and estuaries, and the inland shores of coastal barrier islands. In Florida, it is also found along ditches, in old fields, and in other disturbed areas.[6] Other habitats in the northeastern United States include freshwater tidal marshes and open woods and thickets along the seacoast.[5]

The flowers produce abundant nectar that attracts various butterflies, including the Monarch (Danaus plexippus).[6] These dense shrubs also provide wildlife food and cover.[6]

Invasiveness

Leaves, and long thin seeds with fluffy hairs for windblown dispersal

In Australia, B. halimifolia is an invasive species along the coast of southern Queensland and New South Wales.[1] As biological control the rust fungus Puccinia evadens is used.[8] The species has also become naturalized in Europe[6] and in New Zealand.[6]

In the northeastern United States, the species has become common well inland of the shrub's natural range along various major highways where road salt is heavily used,[3] sometimes forming conspicuous displays when flowering in the fall, as along I-95 in Howard County, Maryland.

Toxicity

The seeds of Baccharis halimifolia are toxic to humans.[6]

Uses

Baccharis halimifolia is occasionally cultivated, useful as a hedge or border as well as a specimen plant.[6]

References

  1. 1.0 1.1 1.2 1.3 "Baccharis halimifolia". Flora of North America. Retrieved 11 October 2011.
  2. Hitchcock, A.S., and P. C. Standley (1919). Flora of the District of Columbia and Vicinity (Contributions from the United States National Herbarium, vol.21). Washington: United States National Museum (Reprinted by Kessinger Publishing, LaVergne, Tennessee, 2010). pp. 329 (+42 plates). ISBN 1-4369-8558-7.
  3. 3.0 3.1 "Eastern Baccharis (Baccharis halimifolia))". Pennsylvania Rare Plant Species. Pennsylvania Natural Heritage Program. Retrieved 11 October 2011.
  4. "Species at Risk Conservation Fund 2009 Approved Projects:". Nova Scotia Canada Department of Natural Resources. Retrieved 11 October 2011.
  5. 5.0 5.1 5.2 Tiner, Ralph W., Jr. (1987). A Field Guide to Coastal Wetland Plants of the Northeastern United States. Amherst [Massachusetts]: University of Massachusetts Press. pp. [iii] + 285. ISBN 0-87023-538-9.
  6. 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Brown, Steven H., and Kim Cooperrider. "Baccharis halimifolia". University of Florida Institute of Food and Agricultural Services. Retrieved 12 October 2011.
  7. "Iva frutescens". Flora of North America. Flora of North America. Retrieved 12 October 2011.
  8. Jim Cullen,Mic Julien,Rachel McFadyen: Biological Control of Weeds in Australia. Csiro Publishing, 2012. Seite 91f

Other references

External links

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