APRIL, 1919. XANTHIUM MILLSPAUGH AND SHERFF. 15 



without date, George Vasey (Hb. Field 13470). KENTUCKY: Bowling 

 Green, Oct., 1899, Sadie F. Price (Hb. Mo. 85573). TENNESSEE: 

 Knoxville, vacant lots, July, 1893, A. Ruth (Hb. Mo. 720836). MIS- 

 SOURI: St. Louis, Oct. 23, 1893, H. Eggert (Hb. Mo. 85575, 720560 and 

 720835). TEXAS: Handley, Sept. 23, 1902, /. Reverchon (Hb. Mo. 

 85580). NEW MEXICO: near Pecos, Paul C. Standley 5150 (Hb. Mo. 

 85582; Hb. N. Y.). NEVADA: Verdi, Oct., 1893, C. F. Sonne (Hb. Calif. 

 196334). ARIZONA: Prescott, David Griffiths 7344 (Hb. Mo. 85583). 

 VANCOUVER ISLAND: Nanaimo, July 7, 1887, John Macoun (Hb. N. Y.). 

 WASHINGTON: Walla Walla, July, 1898, Savage, Cameron and Lenocker 

 (Hb. Mo. 85584). CALIFORNIA: Los Angeles, Le Roy Abrams 4181 

 (Hb. Calif. 149138; Hb. Mo. 85589; Hb. N. Y.); Sherman, Ernest 

 Braunton 731 (Hb. Calif. 54178); vicin. Mendocino, H. E. Brown 919 

 (Hb. N. Y.); near Yreka, Geo. D. Butler 991 (Hb. Calif. 163874); 

 Colusa County, ]. Burtt Davy 4277 (Hb. Calif. 36807) ; near Durham, 

 roadsides and fields, A. A. Heller 12655 (Hb. Mo. 802945); San Simeon 

 Bay, July 22, 1876, Dr. Edw. Palmer (Hb. Mo. 85587); Haywards, 

 Nov. 14, 1893, Ivar Tidestrom (Hb. Calif. 36806); Avalon, Santa Cata- 

 lina Isl., Aug., 1902, Blanch Trask (Hb. N. Y.). 



Wallroth (loc. cit.} founded his Xanthium xanthocarpon upon a 

 specimen by Beyrich, from fields between Staunton and Charlottesville, 

 Virginia. The distinctive characters tabulated in his description are 

 entirely too inconstant, however, to serve in distinguishing the species 

 from true X. spinosum L. Thus, for example, Wallroth described the 

 beaks as unequal, the larger one twice stouter than the prickles: 

 ("Rostris inaequalibus, majore aculeis duplo validiore"). In the 

 nearly two hundred specimens of X. spinosum which we have examined, 

 from North America, we have seen several that matched Wallroth's 

 description in these and other respects precisely. Nevertheless these 

 specimens were but slight variations from the more common, short- 

 beaked form regarded by Wallroth as representing the true Xanthium 

 spinosum L. 



Sect. II. EUXANTHIUM DC. Prodr. 5 : 523. 1836; Anoplia Waltr. 

 Beitr. Bot. i n : 229. 1844. Involucri fructigeri rostra apice nunc 

 recta (Tribus I. Orthorrhyncha Wallr. loc. cit.}, nunc in hamum 

 varie inflexum desinentia (Tribus II. Campylorrhyncha Wallr., 

 loc. cit.}, nunc hiatu longitudinali magis minusve contracto reclusa 

 vel teretia, nunc transversim fissa, veluti bivalvia; caulibus erectis 

 saepius purpureo-maculatis; foliis dentatis; spinis ad basim foliorum 

 nullis. 



