Lactuca Scariola L. Prickly Lettuce. 



Naturalized and common. Ontario, Davidson in 1911. San Bernardino, Parish 

 in 1911, where the variety was already abundant. Upland, Johnston in 1917. Na- 

 tive of Europe. 

 Lactuca Scairiola L. var. integrata Gren. & Godr. Prickly Lettuce. 



Naturalized and common. Pasadena, McClatchie in 1895. San Bernardino, estab- 

 lished in a few places. Parish in 1895. Compton, "quite troublesome ■ in places," 

 Braunton in 1896. Los Angeles, "two plants," Davidson in 1896, and in 1907, "one 

 of the most troublesome weeds in the Los Angeles district, even invading the 

 Black Mustard." Claremont, "rare," Johnston in 1918. 



A very recent immigrant, but here, as elsewhere, its diffusion has been rapid. 

 In some places the species first appeared, in others the variety, and even yet 

 there are local differences in the abundance of either. The two are abundant 

 weeds in cultivated grounds, gardens, roadsides and waste places, and in fields 

 where there is sufficient moisture in the soil, but they do not make their way into 

 unbroken dry hills and mesas. While obnoxious weeds these plants have not 

 proved themselves so injurious in most parts of our region as they are reported 

 to be elsewhere. The earliest records for the state are: Berkeley, "becoming 

 established," K. Brandegee in 1890, and Sacramento, (the species), Michner & 

 Bioletti in 1891. First reported in the LTnited States from Cambridge, Mass., in 

 1835. ■'» Native of Europe. 



Cynara Scolymus L. Artichoke. 



An occasional fugitive, long persisting, but usually not greatly spreading. 

 Abundant over a hillside pasture near Rincon, San Diego county. Parish in 1897, 

 and a few plants by a roadside at San Bernardino in 1899. Laguna, Murrieta, and 

 Orange, Johnston in 1918. Native of Europe. 



Centaurea Cyanus L. Corn- flower. 



Los Angeles, "abundant at the racetrack," Nevin in 1904. An occasional escape 

 throughout the state. Native of Europe. 



Centaurea eriophora L. 



Los Angeles, "observed for two seasons on North Avenue 50," Davidson in 

 1911. The only record for the state. Native of southern Europe. 



Centaurea Melitensis L. Sand Bur. 



An early introduction, probably of the mission period; thoroughly naturalized 

 and abundant in fields and by roadsides; especially obnoxious as an aftermath in 

 grain fields; mostly in light soils, but not conlined to them; occasional in unbroken 

 lands. In the Colorado Desert, at Palm Springs, F. Gilman in 1902. A common weed 

 in most parts of the state. The earliest collection is F. Guirardo in 1861. Native of 

 Europe. 



Centaurea repens L. 



A few scattering plants in 1919 in a field of sugar beets on the farm of Mr. 

 A. Decker, at Artesia, Los Angeles county, 2-3 feet high, and seeding abundantly. 

 It is already spreading in both cultivated and uncultivated ground, and proves 

 difficult to eradicate by reason of its perennial rootstocks. Not elsewhere reported 

 from the L'nited States. Native of Eurasia. 



Centaurea solstitiedis L. St. Barnaby's Thistle. 



San Diego, according to Gray,''" but I have seen no specimens from that region. 

 A few casuals at San Bernardino, Parish in 1907. Riverside, "adventive," Reed 

 in 1918. A common weed in Sacramento valley. Native of the Orient. 

 Cnicus benedictus L. Blessed Thistle. 



Casual in Los Angeles, "in two streets only," Davidson in 1918. Occasional in 

 central California. Native of Europe. 



Circium arvense L. Canada Thistle. 



Locally well established in the peat lands about Wintersberg, Orange County, 

 R. K. Bishop in 1917. Occasional in parts of northern California. The earliest re- 

 port is Humboldt Bay, "well established," Rattan in 1879,^' where it still persists, 

 J. P. Tracy in 1916. San Francisco, K. Brandegee in 1892. Said to have first ap- 

 peared in America about the French missions in Canada, and to have been carried 

 thence to New York in hay used by Burgoyne's army in 1777.^- In New Zealand 

 it is miscalled "California Thistle."^ Native of Europe. 



Arctium Lappa L. Burdock. 



Riverside, Reed about 1910, now somewhat increased. Occasional in a few 



places in central California. At the National Orange Show at San Bernardino in 



1914 an advertising device, well adapted to disseminate this weed, was freely dis- 



""For an account of the spread of the Prickly Lettuce in the U. S. see Parish, 

 S. B. In Muhlenb. 5:121. 1909. 



''"Gray, A. Synootical Flora 1, pt. 2:406. 1884. 



"'Rattan, V. Cal. Horticulturist 9:335. 1879. 



"^Dewey, L. E. IT. S. Dept. Agric. Div. Bot. Circular 27:5. 1900. 



^'Cockayne, L. Rept. Bot. Surv. Stewart Island 66. 1906. 



27 



