20 FIELD MUSEUM or NATURAL HISTORY BOTANY, VOL. IV. 



H. A. Van Hermann 360 (Hb. Field 172254); without locality, in 1865, 

 C. Wright (Hb. Gray). SANTO DOMINGO: Sanchez, Rose, Fitch and Rus- 

 sell 4351 (Hb. U. S. 760483). PORTO Rico: Vieques Isl., Resolucion to 

 Punta Arenas, in sand, /. A. Shafer 2901 (Hb. U. S. 790346). ST. CROIX: 

 Alfred E. Ricksecker 266 (Hb. Field 70621). TORTOLA: Sea-cow Bay, 

 roadside, Britton and Shafer 928 (Hb. U. S. 756709). GUADELOUPE: 

 Pfre Duss 2816 (Hb. Field 202726). 



Apparently no other species of Xanthium has offered heretofore so 

 baffling a problem concerning its true status as has this species. It has 

 been referred at various times to such species as X. strumarium L., X. 

 canadense Mill. ,X .americanum Walt. etc. From X. strumarium L. it differs 

 as a rule very distinctly in having the burs larger, smoother and greenish- 

 brown to reddish in color, not mostly yellowish-green; furthermore, the 

 beaks in X. chinense are longer. X. canadense, as we indicate else- 

 where (p. 26, foot-note) 1 was merely X. orientale L., a species not known 

 authentically in America and differing from X. chinense in having 

 stouter, more coarsely hooked and more hispid prickles and more 

 arcuate beaks. 



In 1768, Philip Miller (Gard. Diet. Edit. VIII, no. 4) advanced a 

 new species of Xanthium which he termed X. chinense. He described 

 the species briefly, "4. Xanthium (chinense) caule inermi ramosa, aculeis 

 fructibus erectis longissimis. China. Xanthium with an unarmed 

 branching stalk, and the spines of the fruit very long and upright." 

 He stated, in addition, that it grew "naturally in China from whence he 

 had received the seeds." But, on inspecting his description, we find it 

 to portray a species which no accounts show ever to have been collected 

 in China, or anywhere else in the Eastern Hemisphere. The nearest 

 approach to the description, as concerns the Orient, would be X. 

 strumarium L. However, not even the Egyptian form 2 of X. stru- 

 marium, the form with spines longer than usual (2.5-3 mm.), has spines 

 so long as to explain or justify Miller's use of the word "longissimis." 

 It is very likely that this seemingly insurmountable discrepancy between 

 description and cited habitat has, in the past, entirely deterred botanists 



1 We have already stated (Field Mus. Bot. 4: 2. 1918) that the name canadense, 

 advanced by Miller in the eighth edition of his Gardener's Dictionary, was equated 

 in the ninth (posthumous) edition with X. orientale L. We may note, further, that 

 Miller originally cited as a synonym of his species the diagnosis of X. orientale L. 

 and gave also "X. majus canadense H. L. 635" (Cf. Thellung,' Verhandl. Bot. Verein 

 Brandenb. 50": 139. 1908). But Thellung (loc. cit. 138) states in detail and, to us 

 very convincingly, the evidence that this "X. majus canadense H. L. 635" is merely 

 the X. orientale of Linnaeus. In fact, Linnaeus himself (Sp. PL Edit. II: 1400. 

 J 763) cited "Xanthium majus canadense. Herm. lugdb. 635 " as the second synonym 

 of his X. orientale. 



J X. antiquorum Wallr., found also in Palestine. Cf. p. 17. 



