''Sporobolus montevidensis'' is a species of
grass known by the common name denseflower cordgrass. Although reclassified after a taxonomic revision in 2014, it may still be referred to as ''Spartina densiflora'' by some users. It is native to the coastline of southern South America, where it is a resident of
salt marshes. It is also known on the west coast of the North America and parts of the
Mediterranean coast as an
introduced species and in some areas a
noxious weed
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...
. In
California it is a troublesome
invasive species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...
of marshes in
San Francisco Bay
San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland.
San Francisco Bay drains water from a ...
and in
Humboldt Bay
Humboldt Bay is a natural bay and a multi-basin, bar-built coastal lagoon located on the rugged North Coast of California, entirely within Humboldt County, United States. It is the largest protected body of water on the West Coast between Sa ...
, where it was introduced during the 19th century from Chile in
ballast.
[''Spartina densiflora'' field guide, Invasive Spartina Project]
/ref>
Description
This perennial grass generally lacks rhizome
In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...
s. It grows in erect clumps of slender stems that can reach 1.5 meters tall. The long, narrow, gray-green leaves are rolled inward, especially when new. The inflorescence is a narrow, dense, spike-like stick of branches appressed together, the unit reaching up to 30 centimetres long. The flowers are colorless and the spikelets are tipped with bristles.
Invasive species
This species has negative impacts on the salt marsh habitat of the California coast. It forms tight clumps of herbage that raise the elevation of the plants in the marsh, keeping the water from flowing in as far as it naturally would, and increasing sediment accumulation.[ It competes with its native relative, ]California cordgrass
''Sporobolus foliosus'' is a species of grass known by the common name California cordgrass. It was reclassified from ''Spartina foliosa'' after a taxonomic revision in 2014. It is native to the salt marshes and mudflats of coastal California and ...
(''Sporobolus foliosus''), and other marsh plants such as pickleweed Pickleweed is a common name used for two unrelated genera of flowering plants:
*'' Batis'', family Bataceae
*''Salicornia
''Salicornia'' is a genus of succulent, halophytic (salt tolerant) flowering plants in the family Amaranthaceae that gro ...
(''Salicornia pacifica'').[ Efforts to eradicate ''Sporobolus montevidensis'' and related hybrids in the San Francisco Bay area reduced the coverage to approximately 41 square meters in 2014, down from about 1.7 hectares (4.2 acres) in 2005.][http://www.spartina.org/documents/2014ProgressReport_wCover.pdf, 2014 ISP Monitoring and Treatment Report, August 2015. Accessed 7/12/18.] However, it continues to expand in the Humboldt Bay region.
References
External links
Jepson Manual TreatmentUSDA Plants ProfileWashington Burke MuseumSan Francisco Estuary Invasive ''Spartina'' ProjectPhoto gallery
montevidensis
Flora of South America
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