16 FIELD MUSEUM OF NATURAL HISTORY BOTANY, VOL. IV. 



2. XANTHIUM STRUMARIUM Linn. Sp. PI. 987. 1753. 



Xanihium priscorum Wallr. Beitr. Bot., i u : 227. 1844. (nom. 



semi-nudum.) 



Xanihium antiquomm Wallr. loc. cit. 229 

 Xanihium strumarium L. var. antiquorum (Wallr.) Ball, Jour. 



Linn. Soc. 16 : 503. 1878. 

 Xanihium abyssinicum Wallr. loc. cit. 230. 

 Xanihium discolor Wallr. loc. cit. 232. 

 Xanihium Roxburghii Wallr. loc. cit. 233. 

 Xanihium brevirostre Wallr. loc. cit. 235. 



Caulis subramosus, pubescens*, 0.4-1.5 m. altus. Folia triangulato- 

 deltoidea et ad basim truncata aut subcordata, 3~5-lobata, utrinque 

 pilis adpressis strigosis vestita et concoloria, petiolis adjectis 0.6-2.5 dm. 

 longa; petiolis laminas subaequantibus aut excedentibus. 'Fructuum 

 (PI. VII, f. 2; PI. VIII, ff. 4-8) corpus ovoideum, aut tumidum et 

 subglobosum, plerumque subviride, pubescens, 0.8-1.4 cm. longum; 

 rostris versus apicem rectis aut incurvatis, 1-2 mm. longis, saepius 

 distantibus; aculeis rectis, ad apicem hamosis, supra glabris, infra plus 

 minusve pubescentibus, circ. 2 (rarius 3) mm. longis. 



DISTRIBUTION: Adventive in Massachusetts and California; native 

 of the north-temperate and tropical regions of the Eastern Hemisphere. 



SPECIMENS EXAMINED: MASSACHUSETTS: Revere, Crescent Beach, 

 Oct. 20, igi2,M.L.Fernald (Hb. Gray). CALIFORNIA: Colorado Desert, 

 Cameron Lake, Mar. 28, 1901, T. S. Brandegee (Hb. Calif. 131246). 



We have already (Field Mus. Bot. 4:2. 1918) noted the collection 

 of genuine X. strumarium in North America, by Fernald, in 1912. It is 

 of interest to note that, several years earlier, this species was collected 

 in the extreme southern part of California, by Brandegee. We have not 

 seen the species from elsewhere in America. 1 



In 1830 Rafinesque listed (Med. Fl. 2 : 275) "2 native species 

 Xanthium crassum and undulatum Raf. mistaken for X. strumarium 

 and orientale by authors." Thus Rafinesque is seen to have realized, 

 at an early date, that the common forms of Xanthium in America were 

 not referable to X. strumarium and X. orientale (see p. 26, foot-note). 

 Rafinesque's two names appear to have been ignored, or indeed over- 

 looked, by botanists since then. But obviously these names can be 

 treated only as nomina nuda, for their precise application to definite 

 American species is impossible. Characteristically, in this connection, 

 Rafinesque fails to mention his own Xanthium maculatum, described, 

 in detail, from the eastern United States eleven years before. There 

 exists, in Gray Herbarium, a good co-type of X. abyssinicum Wallr. 

 (W. Schimper 1343). This specimen we are entirely unable to separate 



_ 1 At least as an escaped plant. We have seen good fruiting material however, 

 raised by Dr. John M. Adams at Cincinnati, Ohio, in 1918, from seed imported with 

 soy-beans from Manchuria (specimen in Hb. Ohio Agr. Exp. Station). 



