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



8. XANTHIUM LEPTOCARPUM Millspaugh and Sherff, Field Mus. Bot. 



4: 3, PL I. 1918. 



Caulis superne scaber, 3-5 dm. altus. Folia plus minusve deltoidea 

 et trilobata, dentata, basi cordata aut subtruncata, utrinque setulis 

 adpressis scabrida, petiolis adjectis 7-19 cm. longa, petiolis laminis 

 subaequantibus. Fructuum (PI. VII, f. 8; PL VIII, ff. 30-32) corpus 

 anguste cylindrico-fusiforme, badium, superne sensim angustatum; 

 exteriore facie et basibus aculeorum et rostrorum pubescentibus, 

 glandulosis; 18-40 aculeis remotis, 2-3 aut rare -4 mm. longis; rostris 

 distantibus, arcuatis; rostris et aculeis ad apicem hamosis, rostris 

 crassioribus et paulo longioribus; fructus corpore 1.3-1.6 cm. longo, 

 3.5-5 mm. crasso. 



DISTRIBUTION : Vermont. 



SPECIMENS EXAMINED: VERMONT: Burlington, Sept. 12, 1896, L.R. 

 Jones (Hb. Field 430860, type); Shores of Lake Champlain, Oct. 30, 

 1895, and Sept. 8, 1896, Ezra Brainerd (Hb. Gray). 



This species appears most closely allied with X. Wootoni Cockll. 

 Careful comparisons, however, of the type and supplementary material 

 with authentic specimens (cited below) of X. Wootoni do not permit us 

 to equate the two species. The burs of X. leptocarpum are uniformly 

 much narrower; moreover, they have about twice as many prickles as 

 do those of X. Wootoni and their beaks show no tendency to be more or 

 less cleft. 1 



9. XANTHIUM WOOTONI Cockerell ex De Vries, Sp. and Var. 140. 1905 ;* 



cf. Proc. Biol. Soc. Wash. 16: 187. 1903. 



X. commune var. Wootoni Cockerell, ibid., p. 9. 1903. 



X. Wootoni Auct. ex Index Kew. Suppl. 3: 191. 1908. 



X. oligacanihum Piper, Contrib. U. S. Nat. Herb, n: 551. 



Caulis erectus aut sese extendens, sparsim scabrido-hispidus, 3-6 dm. 

 altus. Folia reniformi-orbiculata aut deltoideo-cordata, obscure lobata, 

 crenato-dentata, setulis minutis adpressis scabrida, petiolis adjectis 

 0.8-1.5 dm. longa, petiolis laminas aequantibus aut paulo excedentibus. 

 Fructuum (PL VII, f. 9; PL VIII, ff. 33-36) corpus oblongum, vel 

 stramineum vel badium vel etiam rubro-fuscum, superne sensim angus- 



1 See also footnote (p. 27) under X. curvescens. 



2 See also Science, New Series, 42: 871. 1915. 



1 We have purposely given the synonomy as fully as we can. Cockerell originally 

 proposed the plant as a variety. But, in accordance with their entirely unjustified 

 method of indexing varieties, subspecies etc., as species, the Biological Society of 

 Washington indexed the plant at the back of their volume as a species. In 1905, 

 De Vries (loc. cit.) first stated the binomial at all creditably and he definitely attrib- 

 uted the name to Cockerell. As the retention of a multitude of taxonpmic binomials, 

 each accredited merely to some anonymous author (e.g., "Auct." in Index Kew. 

 loc. cit.) can result only in endless confusion in the future, we feel ourselves in accord 

 with the spirit of the Vienna Code (Internat. Rules Bot. Nomencl., art. 4: 2. 1906) 

 in taking De Vries' book as the place of valid publication. 



