''Nassella tenuissima'' is a species of

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

known by the common names Mexican feathergrass,McLaren D, Whattam M, Blood K, Stajsic V, Hore R. 1999. Mexican feather grass (Nassella tenuissima): a potential disaster for Australia, 12th Australian Weeds Conference, 12–16 September, Hobart, Tasmania, 658–62. finestem needlegrass,''Nassella tenuissima''.
USDA PLANTS Profile. fineleaved nassella,Barkworth, M
''Nassella tenuissima''.
In: Barkworth et al. (eds.), Grass Manual. Flora of North America. and Argentine needle-grass. It is native to the south-western United States, northern Mexico and Argentina. It is well-matched to climate in Australia and can be harmful to the Australian environment. It is still widely referenced in botanical and horticultural literature under its synonym ''Stipa tenuissima'', and has received the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

under that name.

Impacts

It is sometimes used as an ornamental garden plant, but readily escapes, and has become naturalized in the San Francisco area.

In Australia

The availability of ''N. tenuissima'' via the internet and other plant purchasing situations makes its entry and naturalization in Australia almost inevitable. It is similar in appearance to '' Nassella trichotoma'' (serrated tussock) and has been recorded in Australia as a weed initially mistaken for that other invasive species. ''N. tenuissima'' has been described by weed experts as a potential 'disaster for the Australian environment'. In Australia, it is considered a major threat to eucalypt woodlands and native grasslands, with government modelling indicating that up to 169 million hectares could be at risk.Csurhes S. 2008. Mexican feather grass (Nassella tenuissima) – Pest plant risk assessment, Queensland Department of Primary Industries and Fisheries, Brisbane. ''N. tenuissima'' is also likely to have significant impacts on beef and wool production. It is closely related to serrated tussock (''N. trichotoma'') and Chilean needle grass (''N. neesiana''), both designated Weeds of National Significance because they displace pasture grasses and produce seeds that contaminate wool. Serrated tussock, which is estimated to cost

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agriculture more than $40 million annually, is said to be causing a greater reduction in pasture carrying capacity than any other weed in Australia, yet ''N. tenuissima'' is thought to be capable of occupying 6 times the area predicted for serrated tussock.

Pathways

It is illegal to import ''N. tenuissima'' into Australia but it has been imported as a nursery plant under incorrect or outdated names. For example, in 2009 a nursery imported ''N. tenuissima'' seeds by incorrectly labelling them as '' Stipa lessingiana'', which is a permitted import. A similar violation occurred in 1996 when a Victorian nursery imported the seeds by labelling with an earlier valid scientific name, ''Stipa tenuissima''. Mexican feathergrass has also been sold by a nursery in NSW as a native grass 'elegant spear ''Austrostipa elegantissima''.Jacobs S, Everett J, Torres M. 1998. Nassella tenuissima recorded from Australia, a potential weed related to tussock. Telopia 8 (1): 41–6.

eBay eBay Inc. ( ) is an American multinational e-commerce company based in San Jose, California, that facilitates consumer-to-consumer and business-to-consumer sales through its website. eBay was founded by Pierre Omidyar in 1995 and became ...

has banned sale of ''N. tenuissima'' to Australian buyers, but some sellers sell it under the outdated name ''S. teniuissima'' to circumvent the ban.

Biosecurity

According to weed experts, the multiple quarantine breaches highlight the critical need for national risk reduction programs to ensure correct labelling, monitor online sales and enforce biosecurity laws to prevent illegal sales.

References

tenuissima Bunchgrasses of North America Grasses of Mexico Flora of Baja California Natural history of the San Francisco Bay Area {{Pooideae-stub