Finestem needlegrass (Nassella tenuissima)

*Nassella tenuissima*, commonly known as Mexican feathergrass, fineleaved nassella, finestem needlegrass, and Argentine needle-grass, is a grass species native to the southwestern United States, northern Mexico, and Argentina. It poses a significant risk to the Australian environment due to its ability to adapt well to the local climate and naturalize easily. Often used as an ornamental plant, it has escaped cultivation and become established in places like the San Francisco area. The widespread availability of this grass through online sales and other channels increases the likelihood of its introduction and spread in Australia. Notably, it resembles *Nassella trichotoma* (serrated tussock) and has been mistakenly identified as such in Australia, further complicating its management as an invasive weed.