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



tis) plus minusve elongatis, imis etiam i . i m. longis. Folia non perspicue 

 crassa, subdeltoidea, tri-aut quinquelobata et basi cordata, serrata, 

 utrinque setulis adpressis scabra, petiolis adjectis 0.7-2.3 dm. longa, 

 petiolis laminis subaequantibus. Fructus (PI. VII., f. 5; PL VIII., 

 ff. 21-23) saepe numerosi (circum 1850 in uno specimine observatis, ex 

 littera Shullii) ; corpore late ovoideo aut subgloboso, vix pubescenti sed 

 glandulis minutissimis numerosis vestito, 0.9-1.1 cm. longo et 4.5-7 mm. 

 crasso; rostris rectis aut non ranter arcuatis, 3-4 mm. longis; aculeis 

 levibus et rectis sed ad apicem hamosis, rostris subaequantibus. 



DISTRIBUTION: Missouri and Kansas. 



SPECIMENS EXAMINED: MISSOURI: Randolph, "a very common 

 weed," Kenneth K. Mackenzie 387 (Hb. Mo. 85408); Jasper County, 

 La Russel, in waste places along railroads and in fields, Ernest J. Palmer 

 1301 (Hb. Mo. 46004 and 756629). KANSAS: Lawrence, breeding 

 grounds of Univ. of Kansas, Sept., 1913, from original plants obtained 

 on northern edge of Wakarusa flood plain about 0.5 km. south of 

 Mount Oread, Charles A. Shull (type in Hb. Field 477325); Lawrence, 

 breeding grounds of Univ. of Kansas, Sept., 1917, idem (Hb. Field 

 477328; lineal descendant from type material); Lawrence, in 1917, idem 

 (Hb. Field 477326; burs from typical plant growing wild); Lawrence, 

 breeding grounds of Univ. of Kansas, in 1917, idem (Hb. Field 477327; 

 burs from lineal descendants of type material). 



In 1915, Shull (loc. tit.), writing upon the physiological isolation of 

 types in Xanthium, described this species. Unfortunately, however, 

 no Latin diagnosis was published (as required by Article 36 of the 

 International Rules of Nomenclature, adopted at Vienna in 1905), 

 and so the name X. globosum must be regarded as having been hereto- 

 fore unbinding and based upon a foundation very insecure. Early in 

 1918 we took the liberty of writing to Dr. Shull regarding the 

 proper publication of a complete taxonomic description in Latin. Dr. 

 Shull promptly replied in a most cordial manner and very generously 

 placed at our disposal, for publication, not only descriptive notes and 

 photographs, but a sheet of the original type material, also other sheets 

 bearing lineal descendants of the type material etc. We have thought 

 it best to draw up our description rather closely from these sheets, 

 hence a somewhat narrower description has been presented than would 

 have been the case had we included the variations observed in the 

 Missouri specimens. 



A study of ShulFs several specimens shows a high degree of uni- 

 formity among the fruits. The species is probably nearest to X. chinense 

 Mill., with which it perhaps intergrades, or hydridizes at times if left 

 to itself. We have seen specimens from Maryland and from Iowa 

 (G. H. Shull 392, along shore of Chesapeake Bay, south of Havre de 



