APRIL, 1919. XANTHIUM MILLSPAUGH AND SHERFF. 37 



15. Xanthium australe sp. nov. PL XIII. 



Caulis scabridus, plus minusve maculis purpureis parvis linearibus 

 punctatus, verisimiliter 0.5-1 m. altus. Folia petiolata, trinervia, 

 deltoideo-cordata, saepe obscure lobata, dentata, utrinque setulis minu- 

 tis adpressis vestita, petiolis adjectis 0.8-2 dm. longa, petiolis laminis 

 subaequantibus. Fructuum (PI. VII, f. 15; PL IX, ff. 16-18) corpus 

 ovoideo-subglobosum, subsparsim glanduloso-pubescens aut glabratum, 

 0.9-1.1 cm. longum et 6-7 mm. crassum (aut etiam 1.3-1.5 cm. longum 

 et 8-9 mm. crassum, in specimine chilensi), aculeis confertis armatum; 

 rostris attenuatis, rectis aut paulo inflexis, ad apicem subrectis aut 

 uncinatis, infra pubescentibus, 6-9 mm. longis; aculeis tenuibus, rectis 

 aut paulo arcuatis, infra nee dense nee longe pubescentibus (in specimine 

 chilensi quibusdam aculeis glandulosis et non pubescentibus), supra 

 glabris, ad apicem uncinatis, 4-5 mm. longis. 



DISTRIBUTION: Mexico, Paraguay and Chile. 



SPECIMENS EXAMINED: TAMAULIPAS: vicin. of La Barra, 8 km. east 

 of Tampico, at sea-level, Dr. Edward Palmer 275 (Hb. U. S. 463216, 

 type). PARAGUAY: Asuncion, Thomas M or ong 807 (Hb. N. Y.). CHILE: 

 Valparaiso, Dr. Mertens (ex Hb. Acad. Petrop., in Hb. Gray). 



The long fruiting beaks of this species suggested to us at first an 

 affinity with the long-beaked West Indian form of X. chinense Mill. 

 (X. longirostre Wallr.). A consideration, however, of the other fruit 

 characters, as well as of foliage, shows no further relationships of a 

 specific nature. 



There is a slight possibility that this is the species which Vellozo had 

 in mind when figuring his Xanthium brasilicum. But a careful inspec- 

 tion of Vellozo's plate (Fl. Flum. 10: tab. 23. 1827) shows it to be all 

 too crude and lacking in definite detail to permit of satisfactory inter- 

 pretation. 1 Indeed, if the plate be at all accurate, it clearly represents 

 some other species, for the characters of the bur as there shown are not 

 those of X. australe. 2 



1 It is surprising to find that Baker (Martius Fl. Bras. 6 ra : 147. 1884), notwith- 

 standing the crudity of this plate, actually made it the basis for a new combination 

 in nomenclature, X. strumarium L. var. brasilicum (Velloz.) Baker. 



2 We have seen no authentic material of the inadequately described X. homo- 

 thalamum of Sprengel (Neue Entdeck. i: 259. 1820) from Brazil. We note that 

 the name X. homothalamum was entirely omitted by Baker from his treatment of 

 Brazilian Xanthia (Martius Fl. Bras. 6 m : 147. 1884). Sprengel himself appears to 

 have seen only scanty material of the plant ("Licet haut perfecta huius plantae 

 exemplaria investigare potuerim," loc. cit., p. 260). He described the fruits briefly: 

 "In ambitu sex aut octo drupae oblongae sulcatae, aculeis flavis uncinatis armatae. 

 Singulae continent semen testa fusco-nigra obductum, in quo, sine albumine, embryo 

 rectus oblongis cotyledonibus mediocriter carnosis, sedet." We find nothing in his 

 description which might justify the reference of our X. australe to X. homothalamum. 



