Malta starthistle, Maltese star-thistle, Malta starthistle, Maltese star thistle, Napa thistle, spotted knapweed, tocalote
- Centaurea melitensis is a winter annual with a yellow-flowered, spiny head that can reach a height of 3.3 ft. (1 m). tall.
- Leaves are alternate, linear or narrowly oblong with smooth, toothed margins. Leaf bases are decurrent and give the stems a winged appearance.
- Flowers are yellow, 0.5 in. (1.3 cm) across, and surrounded by sharp, tan, 0.5 in. (1.3 cm) long, spiny cobwebbed bracts. Blooming occurs from April to September.
- The fruit are 0.08-0.12 in. (2-3 mm) in length, grayish to tan in color with deeply notched bases and tan bristles that are 0.04-0.12 in. (1-3 mm) long.
- Ecological Threat
- Centaurea melitensis prefers disturbed areas such as grasslands, open woodlands, roadsides, fields, and pastures. It is native to Europe and North America.
- Global Invasive Species Database. 2011. Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission
- University of California, Jepson Flora Project
- Texas Invasive Plant and Pest Council
- California Invasive Plant Council
- USDA NRCS PLANTS
- USDA ARS GRIN
Images from Bugwood.org