Cenchrus longispinus explained

Cenchrus longispinus is a species of grass, also known as spiny burr grass or gentle Annie or picco. Its fruits are clumped into "burrs" with sharp, barbed spines that can penetrate the hides and mouth of grazing animals. They can also become lodged in human clothing and skin, causing some discomfort.^[1] This activity is important for the plant's seed dispersal, as the plant is a summer annual. ^[2] The species has a prostrate habit when there is no competition for light.

The species is native to North America and is considered as a noxious weed in Europe, Australia and New Zealand where it was introduced.^{[3] [4] [5] [6] [7] [8] [9] [10]}

Notes and References

1. https://www.biodiversitylibrary.org/page/609801#page/404/mode/1up Fernald, Merritt Lyndon 1943. Virginian botanizing under restrictions. Rhodora 45(538): 357-413
2. https://www.illinoiswildflowers.info/grasses/plants/sandbur.htm#:~:text=Sandbur%20(Cenchrus%20longispinus)&text=Description%3A%20This%20grass%20is%20a,or%20sprawl%20across%20the%20ground. Hilty, John. Sandbur.
3. http://apps.kew.org/wcsp/namedetail.do?name_id=403957 Kew World Checklist of Selected Plant Families
4. http://www.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_grasses_spiny_burr Victoria, Australia, Noxious Weed site
5. http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&state=&s=&ibra=all&card=G15 Distribution in Australia, native origin
6. DAISIE (eds.). 2009. Handbook of Alien Species in Europe. Springer, Dordrecht. 399 p. 
7. Caro, J. A. & E. Sanchez. 1969. Cenchrus. In: A. Burkart, Gramineas. 2: 437–445. In A. E. Burkart (ed.) Fl. Il. Entre Ríos. Instituto Nacional de Tecnología Agropecuaria, Buenos Aires
8. DeLisle, D. G. 1963. Taxonomy and distribution of the genus Cenchrus. Iowa State College Journal of Science 37(3): 259–351
9. Herrera Arrieta, Y. 2014. Additions and updated names for grasses of Durango, Mexico. Acta Botánica Mexicana 106: 79–95
10. Sousa Sánchez, M. & E. F. Cabrera Cano. 1983. Flora de Quintana Roo. Listados Florísticos de México 2: 1–100