Xanthiuvi> 151 



branches erect, slender, nearly heads acute ; pores unequal, 

 irregular, small. 



A small species, three inches liigh, found at Oysterbay, 

 on rocky bottoms, rare ; stem with few branches, and imper- 

 fect ones, like knobs. Substance stupose. Branches refund, 

 alternate, small. Pores without any determinate shape. 



Art. XII. Memoir on the Xanthium maculaium, a JVew 

 Species from the State of JVew-York, ^c. by C. S. 

 Rafinesque, Esq. 



Jl URSH and Michaux mention only one species of American 

 Xanthium, the X. strumaritim, while there are three noticed 

 in the catalogue of Dr. Muhlenberg, the above species, and the 

 X. orientale, and X. spinosum. The first and the last are 

 natives of Europe, and have been naturalized in the United 

 States, with many other plants. The species called X. orientale 

 by Dr. Muhlenberg, appears however to be a native ; but the X. 

 orientate of Linnaeus, is a native of Siberia, Japan, and the East: 

 Indies ; and when plants are found to grow in such opposite 

 quarters of the globe, a strong presumption arises that they 

 are not identical species, which presumption has been con- 

 firmed by experience in many instances, whenever the plant« 

 of both countries have been accurately examined. DecandoUe. 

 in the French Flora, (2d edit, of 1815.) vol. 6. p. 360. 

 describes, under the name qf X. macrocarpon, a species found 

 in France, and which he takes to be the real X. orientale of 

 Linnaeus. He has changed its name, because, he says, that if 

 is not certain that the X. orientale grows in Asia ; or, if any 

 grows there, that it is identic with his species ; which, how- 

 ever, is really the X. orientale of Linnajus, Son, Lamark, and 

 Gaertner. He adds, that he possesses in his herbarium, a 

 species from Canada, different from his X. macrocarpon which 

 has been" figured by Morison, on whose authority some authors 

 have asserted that the X. orientale grew in Canada, mistaking 

 his figure for that plant. 



