COMPOSITAE (COMPOSITE FAMILY) 519 



Means of control 



Prevent seed production, either by cutting while in first bloom 

 or by wholly uprooting. The labor of hand-pulling in alfalfa and 

 grain fields is worth the cost, if expensive seed is saved from con- 

 tamination and the ground is kept from being fouled for another 

 season. 



MALTESE THISTLE 

 Centatirea melitensis, L. 



Other English names: Napa Thistle, Toealote. 



Introduced. Annual. Propagates by seeds. 



Time of bloom: June to September. 



Seed-time: July to October. 



Range: Atlantic States, mostly in the neighborhood of seaports; 



also on the Pacific Coast ; casual in other places. 

 Habitat: Fields, pastures, waste places. 



As a weed this plant is most common and troublesome on the 

 Pacific Coast, and it is by means of Californian seed grain that it 

 has found its way into many new localities. It is an arduous task 

 to cleanse the smooth, wedge-shaped achenes from such seed, but 

 less strenuous than fighting the growing weeds. 



Stem stout, much branched, one to two feet tall. Flower-heads 

 yellow, which cause it to be often confused with St. Barnaby's 

 Thistle ; but it differs from the latter in that its hairy covering is 

 roughish instead of being soft and floccose ; also the leaves are 

 but slightly decurrent, the lower ones pinnatifid, the upper ones 

 very narrow and mostly entire. Heads terminal, about a half- 

 inch broad, sometimes in clusters of two or three but often solitary ; 

 bracts of the involucre stiff, the inner row terminated with weak, 

 ascending, purplish spines ; the intermediate row with short, 

 rigid, divergent spines, about a quarter-inch in length, either 

 simple or with one or two shorter ones at base ; and the outer row 

 having very short, palmatifid spines. Achenes light gray, with 

 pappus often in triple rows, the central row longest, the inner and 

 outer ones very short. 



The same measures should be used for its control as for St. 

 Barnaby's Thistle. 



