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Xanthium L., Sp. Pl. : 987 (1753).

Xanthium L. sect. Acanthoxanthium DC., Prodr. 5: 523 (1836). Type: not cited. [Note: Frequently Millspaugh & Sherff (1918) are cited as having selected the lectotype as Xanthium spinosum L., but no such statement was made by them.]

Xanthium L. sect. II. Akanthoplium Wallr., Beitr. Bot. 1(2): 228/241 (1844), nom. illegit. superfl., based on Xanthium sect. Acanthoxanthium DC.

Acanthoxanthium (DC.) Fourr., Ann. Soc. Linn. Lyon, ser. 2, 17: 110 (1869). Type: Acanthoxanthium spinosum (L.) Fourr. = Xanthium spinosum L.

Lectotype (selected by Fourreau, Ann. Soc. Linn. Lyon., ser. 2, 17: 110 (1869)): Xanthium strumarium L.

References

Bel, J. (1893). Anomalie ou varit du Xanthium spinosum (X. spinosum var. inerme). Rev. Bot. Bull. Mens. 11: 481482.

Cronquist, A. (1994). Xanthium. In: A. Cronquist, A. H. Holmgren, N. H. Holmgren, J. L. Reveal & P. K. Holmgren, Intermountain Flora: Vascular plants of the Intermountain West, U. S. A. Vol. 5. Asterales. New York Botanical Garden, New York. pp. 6465.

Lve, D. (1975). The genus Acanthoxanthium (DC.) Fourr. revived. Lagascalia 5: 5571.

L ve, D. & P. Dansereau. (1959). Biosystematic studies on Xanthium: taxonomic appraisal and ecological status. Canad. J. Bot. 37: 173208.

Millspaugh, C. F. & E. E. Sherff. (1918). New species of Xanthium and Solidago. Field Mus. Nat. Hist., Bot. Ser. 4(1): 17, plates IVI.

Millspaugh, C. F. & E. E. Sherff. (1919). Revision of the North American species of Xanthium. Field Mus. Nat. Hist., Bot. Ser. 4(2): 954, plates VIIXIII.

Parodi, L. R. (1927). El nombre especfico del abrojoí¸™í³” y las especies argentinas del gnero Xanthiumé“”. Physis 8(No. 31): 468480.

Robinson, H. (2006). Xanthium. In: G. Harling & L. Andersson (eds), Flora of Ecuador, No. 77(1): 190(6). Compositae-Heliantheae, Part 1: Introduction, genera MZ. Botanical Institute, Gteborg University, G teborg & Section for Botany, Riksmuseum, Stockholm. pp. 218222.

Wallroth, F. W. (1844). Monographischer Versuch ber die Gew chs-Gattung Xanthium Diosc. In: Beitrge zur Botanik. Eine Sammlung monographischer Abhandlungen ber besonders schwierige Gewchs-Gattungen der Flora Deutschland von Dr. Friedr. Wilh. Wallroth. Hofmeister, Leipzig. Hefte 2. [125]-252 [Xanthium 219íŸ™í¶–244]. [Note: this work presented a numbered synoptic treatment, which included diagnoses of Wallroths new species, followed by an in expanso treatment of the taxa. In several instances different names were provided in the latter, or the species number changed. Wallroth cited Xanthium Diosc. rather than ascribing the genus to Linnaeus, and incorrectly used the rank of tribe beneath the sectional division of the genus.]

Widder, F. J. (1923). Die Arten der Gattung Xanthium. Beitrge zu einer Monographie. Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 1222.

Widder, F. J. (1925). bersicht ber die bisher in Europa beobachteten Xanthium-Arten und Bastarde. Feddes Repert. Spec. Nov. Regni Veg. 21(820): 273305

Widder, F. J. (1964). Die Ver nderlichkeit von Xanthium spinosum. Phyton (Horn) 11(1 & 2): 6982.

Note: Cronquist (1994: 6465) accepted a broad species concept long before Lves works on the genus, although still accepting 3 spp. in the genus. The southern South American species, X. ambrosioides Hook. & Arn., is included within a slightly broader concept of X. spinosum given in this checklist below. If considered as a separate entity it is easy to separate out; it is not present in Bolivia, but rather an endemic of Argentina (Patagonia).

Note: Names of hybrids have been omitted from the following list, and only one name could not be traced X. spinosum L. í¸‰í¶‘forma acutifolium D. N. Christiansen 1929: 70, a name cited by Widder (1964: 76) as a synonym of X. spinosum L. var. laciniatum (Scheuerm. & Thell. ex Widder) Widder.

Key to species

Petiole subtended by an axillary 3-fid spine; leaves narrowly rhomboid, discolorous, whitish beneath; bur beakless or with 1 beakX. spinosum

Plants spineless; leaves triangular, base cordate, concolorous; bur with 2 beaksX. strumarium

Xanthium acerosum Greene, Pittonia 4: 63 (1899) = Xanthium strumarium L.

Xanthium acutilobum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 6 (1918) = Xanthium strumarium L.

Xanthium acutum Greene, Pittonia 4: 62 (1899) = Xanthium strumarium L.

Xanthium affine Greene, Pittonia 4: 60 (1899) = Xanthium strumarium L.

Xanthium albinum (Widder) Scholz & Sukopp, Verh. Bot. Vereins Brandenb. 98-100: 47 (1960), nom. nov. = Xanthium strumarium L.

Xanthium albinum (Widder) H. Scholz ssp. ripicola (Holub) J. Dostal, Folia Mus. Rer. Nat. Bohem. Occid., Bot., 21: 12 (1984) = Xanthium strumarium L.

Xanthium ambrosioides Hook. & Arn., J. Bot. (Hooker) 3(No. 22): 310 (1841) = Xanthium spinosum L.

Xanthium americanum Walt., Fl. Carol. : 231 (1788) = Xanthium strumarium L.

Xanthium antiquorum Wallr., Beitr. Bot. 1(2): 229 (1844) = Xanthium strumarium L.

Xanthium arcuatum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 4 (1918) = Xanthium strumarium L.

Xanthium arenarium Lasch, Bot. Zeit. 14: 411 (1856) = Xanthium strumarium L.

Xanthium aridum St.John, Northw. Sci. 2(3): 93, fig. 4 (1928) = Xanthium strumarium L.

Xanthium armatum Humb. & Bonpl. ex Wallr., Beitr. Bot. 1(2): 242 (1844) = Xanthium spinosum L.

Xanthium artemisioides (Willd.) Delpino, Studi Lign. Anem. Comp. Artem. : 18 (1871) = Ambrosia arborescens Mill.

Xanthium australe Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser., 4(2): 37 (1919) = Xanthium strumarium L.

Xanthium barcinonense Sennen, Bull. Gogr. Bot. 24 (Nos. 295-297): 224 (1914) = Xanthium strumarium L.

Xanthium brasilicum Vell., Fl. Flum. Icones 10: tab. 23 (1831) = Xanthium strumarium L.

Xanthium brevirostre Wallr., Beitr. Bot. 1(2): 228/235 (1844) = Xanthium strumarium L.

Xanthium bubalocarpon Bush, Rep. (Annual) Missouri Bot. Gard. 17: 123 (1906) = Xanthium strumarium L.

Xanthium californicum Greene, Pittonia 4: 62 (1899) = Xanthium strumarium L.

Xanthium calvum Millsp. & Sherff, Publ. Field Mus. Nat. Hist. Bot. Ser., 4: 35 (1919) = Xanthium strumarium L.

Xanthium campestre Greene, Pittonia 4: 61 (1899) = Xanthium strumarium L.

Xanthium canadense Mill., Gard. Dict., ed. 8, No. 2 (1768) = Xanthium strumarium L.

Xanthium canescens (Costa) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 121 (1923) = Xanthium spinosum L.

Xanthium catharticum Kunth in Humb., Bonpl. & Kunth, Nov. Gen. Sp. Pl. 4 (ed. folio): 216 (1818) = Xanthium spinosum L.

Xanthium cavanillesii Schouw, Ann. Sci. Nat. Bot. 12: 357 (1849) = Xanthium strumarium L.

Xanthium cenchroides Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(2) : 30 (1918) = Xanthium strumarium L.

Xanthium chasei Fernald, Rhodora 48: 66 (1946) = Xanthium strumarium L.

Xanthium chinense Mill., Gard. Dict. ed. 8: No. 4 (1768) = Xanthium strumarium L.

Xanthium chinense Mill. var. globuliforme C. Shull, Bot. Gaz. 83: 385 (1927) = Xanthium strumarium L.

Xanthium cloessplateaum D. Z. Ma, Acta Bot. Bor.-Occid. Sin. 11(4): 346 (1991) = Xanthium strumarium L.

Xanthium commune Britton, Man. Fl. North. States Canad.: 912 (1901) = Xanthium strumarium L.

Xanthium cordifolium Stokes, Bot. Mat. Med. 4: 380 (1812) = Xanthium strumarium L.

Xanthium crassifolium Millsp. & Sherff, Publ. Field Mus. Nat. Hist. Bot. Ser. 4(1): 5 (1818) = Xanthium strumarium L.

Xanthium cuneatum Moench, Meth. Suppl. : 300 (1802) = Xanthium strumarium L.

Xanthium curvescens Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(2): 25 (1919) = Xanthium strumarium L.

Xanthium cylindricum Millsp. & Sherff, Publ. Field. Mus. Nat. Hist., Bot. Ser. 4(1): 4 (1918) = Xanthium strumarium L.

Xanthium decalvatum Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 72 (1923) = Xanthium strumarium L.

Xanthium discolor Wallr., Beitr. Bot. 1(2): 232 (1844) = Xanthium strumarium L.

Xanthium echinatum Murray var. cavanillesii (Schouw) O. Bol s & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988] = Xanthium strumarium L.

Xanthium echinatum Murray ssp. italicum (Moretti) O. Bols & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988] = Xanthium strumarium L.

Xanthium echinatum Murray var. italicum (Moretti) O. Bol s & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988] = Xanthium strumarium L.

Xanthium fruticosum L.f., Suppl. Pl. : 418 (1782), based on Ambrosia arborescens Mill. = Ambrosia arborescens Mill.

Xanthium fuscescens Jord. & Fourr., Brev. Pl. Nov. fasc. 1: 36 (1866) = Xanthium strumarium L.

Xanthium glabratum Britton, Man. Fl. North. States Canad. : 912 (1901) = Xanthium strumarium L.

Xanthium glanduliferum Greene, Pittonia 4: 61 (1899) = Xanthium strumarium L.

Xanthium globosum C. Shull, Bot. Gaz. 59: 482 (1915) = Xanthium strumarium L.

Xanthium homothalamum Spreng., Neue Entdeck. 1: 259 (1819 or before Aug. 1820) = Xanthium strumarium L.

Xanthium inaequilaterum DC., Prodr. 5: 523 (1836) = Xanthium strumarium L.

Xanthium indicum DC., Prodr. 5: 523 (1836) = Xanthium strumarium L.

Xanthium inflexum Mack. & Bush, Rep. Missouri Bot. Gard. 1905, 106 (1905) = Xanthium strumarium L.

Xanthium italicum Moretti, Diar. Phys. Chem. Hist. Nat. 5: 8 (1822); De quibusdam plantis Italiae, Decas Quinta : 8 (1822) = Xanthium strumarium L.

Xanthium italicum Moretti var. albinum Widder, Feddes Repert. Spec. Nov. Regni Veg. 20: 105 (1923) = Xanthium strumarium L.

Xanthium japonicum Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 31 (1923) = Xanthium strumarium L.

Xanthium leptocarpum Millsp. & Sherff, Publ. Field Mus. Nat. Hist. Chicago, Bot. Ser. 4: 3 (1918) = Xanthium strumarium L.

Xanthium longirostre Wallr., Beitr. Bot. 1(2): 237 (1844) = Xanthium strumarium L.

Xanthium macounii Britton, Man. Fl. North. States Canad. : 913. (1901) = Xanthium strumarium L.

Xanthium macrocarpum DC., Fl. France, Suppl. [5], 6: 356 (1815) = Xanthium strumarium L.

Xanthium macrocarpum DC. [var.] b glabratum DC., Prodr. 5: 523 (836), nom. illegit. pro X. americanum Walt. & X. canadense Mill. = Xanthium strumarium L.

Xanthium macrocarpum DC. var. laciniatum Pouzolz, Fl. Dp. Gard 2(1): 2, tab. 6 (1857) = Xanthium strunarium L.

Xanthium maculatum Raf., Amer. Monthly Mag. : 344 (1818); Amer. J. Sci., Ser. 1(1): 151 (1819) = Xanthium strumarium L.

Xanthium medium Nossotovsky, Izv. Imp. Bot. Sada Petra Velikago [Bull. Jard. Imp. Bot. Pierre le Grand] 14(46): 454 (1914) = Xanthium spinosum L.

Xanthium mongolicum Kitag., Rep. First Sc. Exped. Manchoukuo, Sect. 4, 4: (Index Fl. Jehol.): 97 (1936) = Xanthium strumarium L.

[Xanthium monoicum Gilib., Fl. Lituan. Inch. 1: 170 (1782), opera utique oppressa = Xanthium strumarium L.]

Xanthium multifidum Larranaga, Escritos Damaso Antonio Larranaga 1: 28, l m. 117 (1922) [Pub. Inst. Hist. Geog. Urug.], nom. illegit., inval. = Xanthium spinosum L.

Xanthium natalense Widder, Feddes Repert. Spec. Nov. Regni Veg. 51: 274 (1937) = Xanthium strumarium L.

Xanthium nigri Ces., Pass. & Gibelli, Comp. Fl. Ital. : 437 (1877) = Xanthium strumarium L.

Xanthium occidentale Bertol., Lucubr. re Herb. : 38 (1822), nom. illegit., superfl. = Xanthium strumarium L.

*Xanthium orientale L., Sp. Pl. (ed. 2) 2: 1400 (1763) = Xanthium strumarium L.

Xanthium orientale L. var. albinum (Widder) Adema & M. T. Jansen, Gorteria 9(9): 302 (1979) = Xanthium strumarium L.

Xanthium orientale L. forma laciniatum (Pouzolz) Thell. ex Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 80 (1923) = Xanthium strumarium L.

Xanthium orientale L. var. riparium (Itzigs. & Hertsch) Adema & M. T. Jansen, Gorteria, 9(9): 303 (1979) = Xanthium strumarium L.

Xanthium oviforme Wallr., Beitr. Bot. 1(2): 240 (1844) = Xanthium strumarium L.

Xanthium palustre Greene, Pittonia 4: 63 (1899) = Xanthium strumarium L.

Xanthium parvifolium DC., Prodr. 5: 524 (1836) = Xanthium spinosum L.

Xanthium pennsylvanicum Gand., Bull. Soc. Bot. France 65: 54 (1918), nom. illegit. = Xanthium strumarium L.

Xanthium pensylvanicum Wallr., Beitr. Bot. 1(2): 240 (Aug. 1844) = Xanthium strumarium L.

Xanthium pungens Wallr., Beitr. Bot. 1(2): 227 (1844) = Xanthium strumarium L.

Xanthium pungens Wallr. var. cylindricum (Millsp. & Sherff) Widder, Feddes Repert. Spec. Nov. Regni Veg. 20: 167 (1923) = Xanthium strumarium L.

Xanthium pungens Wallr. var. denudatum Widder, Feddes Repert. Spec. Nov. Regni Veg. 20: 69 (1923) = Xanthium strumarium L.

Xanthium pungens Wallr. var. globosum (Shull) Widder, Feddes Repert. Spec. Nov. Regni Veg. 20: 166 (1923) = Xanthium strumarium L.

Xanthium riparium Itzigs. & Hertsch, Bot. Zeit. 12: 34 (1854) = Xanthium strumarium L.

Xanthium riparium Lasche, Bot. Zeit. 14: 412 (1856), nom. illegit. = Xanthium strumarium L.

Xanthium ripicola J. Holub, Folia Geobot. Phytotax., 11(1): 83 (1976), nom. nov. pro X. riparium Lasche = Xanthium strumarium L.

Xanthium roxburghii Wallr., Beitr. Bot. 1(2): 233 (1844) = Xanthium strumarium L.

Xanthium saccharatum Wallr., Beitr. Bot. 1(2): 228 (1844) = Xanthium strumarium L.

Xanthium saccharatum Wallr. ssp. aciculare Widder, Feddes Repert. Spec. Nov. Regni Veg. 21(820): 286 (1925) = Xanthium strumarium L.

Xanthium saccharatum Wallr. ssp. commune (Britton) Widder, Feddes Repert. Spec. Nov. Regni Veg. 21(820): 286 (1925) = Xanthium strumarium L.

Xanthium sibiricum Patrin ex Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 32 (1923) = Xanthium strumarium L.

Xanthium sibiricum Patrin ex Widder var. subinerme (C. Winkler) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 34, 36 = Xanthium strumarium L.

Xanthium silphi[i]folium Greene, Pittonia, 4: 60 (1899) = Xanthium strumarium L.

Xanthium speciosum Kearney, Bull. Torrey Bot Club 24(12): 574 (1897) = Xanthium strumarium L.

Xanthium sphaerocephalum Salzm. ex Ball, J. Linn. Soc., Bot. 16: 503 (1878), nom. nud. pro syn. = Xanthium strumarium L.

*Xanthium spinosum L., Sp. Pl. : 987 (1753). Type: Habitat in Lusitania. 0. Lectotype (selected by Wijnands, Bot. Commelins : 87, 1983): Herb. Linn. No. 1113.3 (LINN).

Xanthium catharticum Kunth in Humb., Bonpl. & Kunth, Nov. Gen. Sp. Pl. 4 (ed. folio): 216 (1818). Type: [Ecuador:] Crescit in Regno Quitensi, prope Chillo et Quito, alt. 1315 hex. 0 Floret Martio. [Humboldt & Bonpland Bonpl. mss. n. 3006. Quito]. Holotype: P-Bonpl.

Xanthium spinosum L. [var.] b brachyacanthum DC., Prodr. 5: 523 (1836). Type: In specimine Brasiliano midi obvio ex comp. Bras. . 867, spinae mult breviores qu m in Europaeis. ... (v.s. in h. Mus. reg. Par.). Holotype: P; isotype: G-DC.

Xanthium parvifolium DC., Prodr. 5: 524 (1836). Type: ? Patr. ign. verisim. Amer. austr. ... (v.s. comm. ab am. Delessert.). Holotype: G-DC.

Xanthium ambrosioides Hook. & Arn., J. Bot. (Hooker) 3(No. 22): 310 (1841). Types: Los Caldanes, Province of Cordova; Dr. Gillies [96]. Buenos Ayres; Tweedie [see note]. Syntypes: K. Note: There is one sheet in K with several collections mounted on it. The Beechey and Chamisso collections are from California in North America and in addition there is one collection by Gillies and two Tweedie collections. One of these is labelled and unnumbered, and likened to Gillies 96, the other unlabelled and numbered on the sheet as 738. Both the Tweedie collections originated from Buenos Ayres.

Xanthium armatum Humb. ex Wallr., Beitr. Bot. 1(2): 228/242 (1844), nom. illegit.

Xanthium xanthocarpon Wallr., Beitr. Bot. 1(2): 229/241 (1844). Type: X. spinosum Beyrich in herb. amiciss. Sporleder./In den vereinigten Staaten und namentlich in Virginien auf freien Feldern zwischen Staunton und Charlotteville von Beyrich im Monat September fruchttragend entdeckt. Holotype: ? Note: In Wallroths earlier key this species was numbered 20 in his listing, not 17 as it appeared later in the fuller description and discussion.

Xanthium eriocarpon Wallr., Beitr. Bot. 1(2): 242 (1844). Type: Xanthium ambrosioides Hook. et Lindl. in lit./ Das von W. Arnott in dem Herbar. general. berol. niedergelegte Exemplar scheint aus Sd-Amerika zu stammen. Holotype: B.

Xanthium spinosum L. var. inerme Bel, Rev. Bot. Bull. Mens. 11: 481 (1893). Type: Au mois dao t dernier [1892], nous avons trouv sur les bords du Tarn une vari t tout fait inerme qui a attir notre attention. Nous en avons envoy des grains plusieurs jardins botanique de France et, nous-m me, nous avons fait un semis considrable. [Bel, s.n.] Holotype: ?

Xanthium spinosum L. var. canescens Costa, Introd. Fl. Catalu a : 160 (1864). Type: Hab. ad oras fl Bess pr. Badalona. Holotype: BC or possibly LE (Herbarium Catalonicum).

Acanthoxanthium spinosum (L.) Fourr., Ann. Soc. Linn. Lyon, ser. 2, 17: 110 (1869).

Xanthium medium Nossotovsky, Izv. Imp. Bot. Sada Petra Velikago [Bull. Jard. Imp. Bot. Pierre le Grand] 14(46): 454 (1914). Type: ó’–‘Lauteur [A. Nossotovsky] a decouvert dans le rgion du Don (Stanitza Gnilovskaia pr s de Rostov) une remarquable espce du genre Xanthium ... Holotype: LE.

Xanthium multifidum Larranaga, Escritos Damaso Antonio Larra aga, 1: 28, pl. 117 (1922) [Pub. Inst. Hist. Geog. Urug.]; cf. Gray Herb. Card Cat., Issue 123. Note: This reference is provided in the major databases, yet there is no p. 28 in vol. 1 of Larranagas work. Lm. CXVII is a poor sketch (unnamed á – the name only appearing in the Explicacin at the end of the first volume) of what is undoubtedly of Xanthium spinosum. Since it has no dissections, this can only be considered nom. illegit., inval.

Xanthium canescens (Costa) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 121 (1923).

Xanthium spinosum L. forma laciniatum Scheuerm. & Thell. ex Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 135 (1923). Type: ó‘’‘Hannover, auf den Kartoffelfeldern bei Dhren in inzelnen Exemplaren, mit Wolle vor bergehend eingeschleppt, 10.9.1913, R. Scheuermann. Holotype: GZU.

Xanthium spinosum L. var. pseudinerme Widder, Physis 8(No. 31): 480 (1927). Type: [Argentina:] Buenos Aires: Pueyrredn (F. C. C. A.), leg. A. Burkart no 393, 12-IV-26 (Herb. L. R. Parodi no 7188) ejemplar tipo, det. F. J. Widder. Syntypes: ?GZU.

Xanthium spinosum L. forma praecocius Bitter ex Widder, Phyton (Horn) 11(1 & 2): 75 (1964). Type: Da mir das Original selbst nicht zug nglich war, kann wohl dessen photographische Wiedergabe in Bitter 1908: tab. 9, fig. 1 vorlufig als Lectotypus anerkannt werden.

Xanthium spinosum L. var. synacanthum Widder, Phyton (Horn) 11(1 & 2): 77 (1964). Type: [Britain:] ê¨…í²‘Cabbage field, Charlton, Worcs, V.-c. 37, 15.8.1955, C.W. Bannister, wool advent. fl. of Brit. distrib. by J. E. Lousley No. W/92. Holotype: originally Herb. Lousley, now in RDG.

Xanthium spinosum L. var. laciniatum (Scheuerm. & Thell. ex Widder) Widder, Phyton (Horn) 11(1 & 2): 76 (1964).

Acanthoxanthium spinosum (L.) Fourr. ssp. catharticum (Kunth) D. Lve, Lagascalia 5(1): 64 (1975).

Acanthoxanthium ambrosioides (Hook. & Arn.) D. L ve, Lagascalia 5(1): 66 (1975).

Argentina, Bolivia (Santa Cruz), Brazil, Chile, Ecuador, Uruguay, USA. Widespread as a weed in many tropical and temperate countries, especially in south and central Europe (but a casual further north - Denmark, England, France), Eastern Africa, Mascarenes, South Africa, Turkey.

Xanthium spinosum L. [var.] b brachyacanthum DC., Prodr. 5: 523 (1836) = Xanthium spinosum L.

Xanthium spinosum L. var. canescens Costa, Introd. Fl. Catalua : 160 (1864) = Xanthium spinosum L.

Xanthium spinosum L. var. inerme Bel, Rev. Bot. 11: 481 (1893) = Xanthium spinosum L.

Xanthium spinosum L. var. laciniatum (Scheuerm. & Thell.) Widder, Phyton (Horn) 11(1 & 2): 76 (1964) = Xanthium spinosum L.

Xanthium spinosum L. forma laciniatum Scheuerm. & Thell. ex Widder, Feddes Repert. Spec. Nov. Regni Veg. 20: 135 (1923) = Xanthium spinosum L.

Xanthium spinosum L. forma praecocius Bitter ex Widder, Phyton (Horn) 11(1 & 2): 75 (1964) = Xanthium spinosum L.

Xanthium spinosum L. var. pseudinerme Widder, Physis 8(No. 31): 480 (1927) = Xanthium spinosum L.

Xanthium spinosum L. var. synacanthum Widder, Phyton (Horn) 11(1 & 2): 77 (1964) = Xanthium spinosum L.

Xanthium strumarium L., Sp. Pl. : 987 (1753). Type: Habitat in Europa, Canada, Virginia, Jamaica, Zeylona, Japonia. 0. Lectotype (selected by Rechinger, Fl. Iranica 164: 39, 1989): Herb. Linn. No. 1113.1 (LINN).

*Xanthium orientale L., Sp. Pl., ed. 2, 2: 1400 (1763). Type: ñ‘’‘Habitat in China, Japonia, Zeylona. Lectotype (selected by Jeanmonod in Gamisans & Jeanmonod, Compl. Prodr. Fl. Corse, Asteraceae I: 190, 1998): Herb. Linn. No. 1113.2 (LINN). Note: because this material is immature Wisskirchen in Jarvis & Turland (1998: 369) selected an epitype: Wisskirchen 230 (BM-000576318); isoepitype: BOCH.

Xanthium canadense Mill., Gard. Dict., ed. 8, No. 2 (1768). Type: The second sort grows naturally in North America.

Xanthium chinense Mill., Gard. Dict. ed. 8: No. 4 (1768). Type: The fourth sort grows naturally in China, from whence I have often received the seeds;

[Xanthium monoicum Gilib., Fl. Lituan. Inch. 1: 170 (1782) opera utique oppressa].

Xanthium americanum Walt., Fl. Carol. : 231 (1788). Type: not cited.

Xanthium cuneatum Moench, Meth. Suppl. 300 (1802), nom. illegit. superfl. pro X. orientale L.

Xanthium cordifolium Stokes, Bot. Mat. Med. 4: 380 (1812). Type: Specimen gathered in Soles Garden.

Xanthium macrocarpum DC., Fl. France, Suppl. [5], 6: 356 (1815). Type: Elle a t trouve dans les vignes du bas Languedoc, par Mademoiselle Lucie Dunal. Holotype: ?G.

Xanthium homothalamum Spreng., Neue Entdeck. 1: 259 (1819 or before Aug. 1820). Type: é’‘Habitat in Brasilia, unde Mertensius adlatam largitus est. Sprengel noted Licet haut perfecta huius plantae exemplaria investigare potuerim suggesting that he had poor material available. Holotype: ?

Xanthium maculatum Raf., Amer. Monthly Mag. : 344 (1818); Amer. J. Sci., Ser. 1(1): 151 (1819), nom. nud.

Xanthium italicum Moretti, Diar. Phys. Chem. Hist. Nat. 5: 8 (1822); De quibusdam plantis Italiae, Decas Quinta : 8 (1822). Types: Habitat in multis Italiae locis: illam inveni prope mare in regione Porto di Fermo, eamque abuntissimam secus decursum fluminis Padi a viciniis Augustae Taurinorum Ticinum usque perspexi. Syntypes: ?

Xanthium occidentale Bertol., Lucubr. re Herb. : 38 (1822), nom. illegit. superfl. pro X. orientale L.

Xanthium brasilicum Vell., Fl. Flum. Icones 10: tab. 23 (1831). Type: not cited. [Note: name is valid as it is accompanied by a diagnostic dissection].

Xanthium macrocarpum DC. [var.] b glabratum DC., Prodr. 5: 523 (1836), nom. illegit. incl. X. americanum Walt. & X. canadense Mill.

Xanthium indicum DC., Prodr. 5: 523 (1836). Types: in gypto (Coqueb.!), in ruderatis Indiae orientalis frequens, verisim. etiam in Chin . ... X. Indicum Wall.! cat. et herb. n. 291. Wight herb. ... (v. s.). Syntypes: G-DC. Note: Apart from the Coquebert collection, there are two duplicates of the Wallich 291 material, together with one unlabelled speciment, and one without an obvious collector.

Xanthium inaequilaterum DC., Prodr. 5: 523 (1836). Type: in ruderatis ins. Javae prope Buitenzorg legit cl. Blume. ... (v.s. comm. cl. invent.). Holotype: G-DC.

Xanthium strumarium L. var. canadense (Mill.) Torr. & A. Gray, Fl. N. Amer. 2: 294 (1841-43).

Xanthium priscorum Wallr., Beitr. Bot. 1(2): 227 (Aug. 1844). Type: not cited, but the same as in Xanthium antiquorum Wallr., which was simultaneously published in the same work Note: in WallrothÒ’s account this later appeared as Xanthium antiquorum Wallr. (1844: 229), q.v.

Xanthium abyssinicum Wallr., Beitr. Bot. 1(2): 227/230 (Aug. 1844). Type: Xanthium strumarium Schimp. it. abyss. II. n. 1343./Auf den Sorgho-Feldern Abyssiniens von Schimper d. 19. Juli. 1838 entdeckt. (Herb. amic. Lucae.)

Xanthium pungens Wallr., Beitr. Bot. 1(2): 227/231 (Aug. 1844). Type: not cited.

Xanthium discolor Wallr., Beitr. Bot. 1(2): 228/232 (Aug. 1844). Type: Xanthium indicum Wallich. herb. indic. (1824.) n. 3181. A. in herbar. gener. berolin., Holotype: B

Xanthium roxburghii Wallr., Beitr. Bot. 1(2): 228/233 (Aug. 1844). Type: Xanthium strumarium Willd. herb. n. 17469. fol 6. In Ost-Indien. Roxburgh. Holotype: B

Xanthium brevirostre Wallr., Beitr. Bot. 1(2): 228/235 (Aug. 1844). Types?: Xanthium indicum herb. Wight. n. 1446 [In Ostindien. Wight. (Herbar. gener. berol.)], . var. cordata pl. Wallich. n. 3181. Syntypes: ?B. Isosyntype: Wallich 3181, K-W.

Xanthium pensylvanicum Wallr., Beitr. Bot. 1(2): 228/236 (Aug. 1844). Types: a glandulosum Xanthium strumarium Beyrich in Herb. amic. Sporleder. von Beyrich auf unfruchtbaren Pltzen bei Ashville (1833) h ufig; b Xanthium occidentale Poepp. fl. pensylv. von Poeppig auf feuchten Wiesen in Pensylvanien im Monat September 1824 entdeckt. The two varieties were described at the same time without reference as to which was typical.

Xanthium longirostre Wallr., Beitr. Bot. 1(2): 228/237 (Aug. 1844). Types: Xanthium macrocarpum C. Ehrenb. n. 195. In Westindien auf St. Thomas und auch auf Haiti von C. Ehrenberg gesammelt (herb. gener. berolin.), und vermuthlich frher schon auf St. Domingo von Bertero entdeckt. Syntypes: B.

Xanthium saccharatum Wallr., Beitr. Bot. 1(2): 228/238 (Aug. 1844). Type: Xanthium macrocarpum Berlandier n. 1865.

Xanthium oviforme Wallr., Beitr. Bot. 1(2): 228/240 (Aug. 1844). Type: á’‘Xanthium canadense Hook. in litt. (herb. general berol.), nec Herm., Mill. et Linn./ Angeblich in Nordamerica und vermutlich in Canada. Holotype: B; isotype: K.

Xanthium antiquorum Wallr., Beitr. Bot. 1(2): 229 (1844). Types: Kotsch. iter. nubic. n. 319., Ehrenb. fl. dalmat. cent. VIII. n. 83./Xanthium Dioscoridis Gundelsh. in herb. general. berol. /An den Ufern des Nils, z. B. bei Chartun in der Provinz Sennaaroder des Tigris. Im Monat Mai mit reifen Frchten; auch in Dalmatien, z. B. bei Castel nuovo von Ehrenberg gefunden und vermuthlich im Orient ziemlich verbreitet.

Xanthium cavanillesii Schouw, Ann. Sci. Nat. Bot., Ser. 3, 12: 357 (1849). Type: Buenos-Ayres. Didrichsen. [ex Index seminum horti academici Hauniensisâ‘’.]

Xanthium riparium Itzigs. & Hertsch, Bot. Zeit. 12: 34 (1854), nom. illegit. superfl. pro X. macrocarpon DC.

Xanthium arenarium Lasche, Bot. Zeit. 14: 411 (1856). Type: not cited, nor for the four unranked named infraspecific taxa.

Xanthium riparium Lasche, Bot. Zeit. 14: 412 (1856). Type: not cited, nor for the four unranked named infraspecific taxa.

Xanthium macrocarpum DC. var. laciniatum Pouzolz, Fl. Dp. Gard 2(1): 2, tab. 6 (1862). Type: Le var. B, rare dans les vignes, Manduel. Holotype: ?

Xanthium strumarium L. var. arenarium (Lasch) Uechtritz, Verh. Bot. Vereins Prov. Brandenburg 34: 210 (1862).

Xanthium fuscescens Jord. & Fourr., Brev. Pl. Nov. fasc. 1: 36 (1866). Type: Hab. in arenosis subhumidis Corsicae; Biguglia prope Bastia, ex dom. E. Revelire.

Acanthoxanthium spinosum (L.) Fourr., Ann. Soc. Linn. Lyon, 2, 17: 110 (1869).

Xanthium nigri Ces., Pass. & Gibelli, Comp. Fl. Ital. : 437 (1877). Type: è’‘Raccolto alle paludi delle Apertole nel Vercellese dal Sig. Avv. F. Negri. Settembre 1869. Holotype: ?

Xanthium sphaerocephalum Salzm. ex Ball, J. Linn. Soc., Bot. 16: 503 (1878), nom. nud. pro syn.

Xanthium speciosum Kearney, Bull. Torrey Bot Club 24(12) : 574 (1897). Type: [USA: Eastern Tennessee: ] Collected by the writer September 16 [1897], near Wolf Creek Station ([T.H. Kearney, Jr.] no. 785) where it grows on the sandy bottom-lands near the French Broad River and is almost certainly indigenous. Isotype: US.

Xanthium varians Greene, Pittonia 4(21): 59 (1899). Type: Shady banks of the Columbia River, Klickitat Co., Washington, Oct. 1893, W. N. Suksdorf, n. 1583, distributed as X. strumarium. Holotype: originally in LCU but probably now in WIS; isotype: US.

Xanthium affine Greene, Pittonia 4(21): 60 (1899). Type: Habitat of the preceding species, and by the same collector, distributed without a specific name, under [Suksdorf] n. 1584. Holotype: originally in LCU, but probably now in WIS; isotype: US.

Xanthium silphi[i]folium Greene, Pittonia, 4(21): 60 (1899). Type: The type of this strongly marked species is of Mr. Suksdorfs collecting from the banks of the Columbia, Sept., 1883, the specimen preserved in the U.S. Herbarium. Holotype: US; isotypes: F 2.

Xanthium glanduliferum Greene, Pittonia 4(21): 61 (1899). Type: Collected at Walsh, Assiniboia, 15 Aug., 1895, by Mr. John Macoun, and distributed for X. Canadense, but the species is evidently new, and thoroughly distinct. The ticket accompanying my specimen bears the Canadian Survey number 10,910. Holotype: originally in LCU.

Xanthium campestre Greene, Pittonia 4(21): 61 (1899). Types: Fertile plains of the Sacramento River, in middle and northern California; the best specimens collected by myself, near Chico, June, 1890; but there exists in the U.S. Herbarium a good one from the Wilkes Expedition obtained near Sacramento. Although unnumbered, there is a Pickering 1361 which may represent the latter collection but is was also used by Widder as the type of his Xanthium decalvatum, q.v. Syntypes originally in LCU but probably now in WIS.

Xanthium californicum Greene, Pittonia 4(21): 62 (1899). Type: Common in middle California, especially about San Francisco Bay, being the X. Canadense of my Manual and of the Flora Franciscana in large part. Holotype: originally in LCU but probably now in WIS.

Xanthium acutum Greene, Pittonia 4(21): 62 (1899). Type: Known by a single specimen obtained at Stockton, California, by Mr. J. A. Sanford, in 1888. Holotype: originally LCU but probably now in WIS. [qv. Tucker et al. 1989: 202]

Xanthium palustre Greene, Pittonia 4(21): 63 (1899). Type: Known only from the brackish marshes of Suisun Bay, middle California. An exceedingly well marked species, referred to by me as an indiginous state of X. Canadense in the Flora Franciscana. Holotype: ?

Xanthium acerosum Greene, Pittonia 4(21): 63 (1899). Type: Known only from the valley of the Red River of the North, where it was collected by the writer [E.L. Greene], near Fargo, North Dakota, 4 Sept., 1893. Holotype: originally at LCU.

Xanthium glabratum (DC.) Britton, Man. Fl. North. States Canad. : 912 (1901).

Xanthium commune Britton, Man. Fl. North. States Canad. : 912 (1901). Type: Type collected by N. L. Britton at Westport, N.Y.

Xanthium macounii Britton, Man. Fl. North. States Canad. : 913. (1901). Type: Goose Island, Lake Winnipeg, Manitoba, J. M. Macoun, Aug. 16, 1884. Specimen in the herbarium of the Geological and Natural History Survey of Canada.

Xanthium inflexum Mack. & Bush, Rep. (Annual) Missouri Bot. Gard. 16: 106 (1905). Type: Sandy bottoms along the Missouri River in western Misosuri. Missouri: Courtney, Bush 869, September 13, 1900, 1916, October 5, 1903, type, 1804, 1806, October 21, 1902. Holotype: MO.

Xanthium oligacanthum Piper, Contr. U.S. Natl. Herb. 11: 551 (1906). Type: Bolles, Walla Walla County, Piper, September 18, 1893; also found at Waitsburg by Horner (no. B272). The type is in the National Herbarium. There is a specimen marked as holotype in US, although clearly this can only be a syntype.

Xanthium bubalocarpon Bush, Rep. (Annual) Missouri Bot. Gard. 17: 123 (1906). Type: TEXAS. Dallas County, [Common on prairie.] Bush 1185, September 29, 1900. Holotype: MO; isotype: US.

Xanthium wootoni Cockerell ex De Vries, Sp. Var. (Ed. 2) : 140 (1905). Type: Last year a very curious instance of a partial loss of prickles was discovered by Mr. Cockerell of East Las Vegas in New Mexico. It is a variety of the American cocklebur, often called sea-burdock, or the hedgehog-burweed, a stout and common weed of the western States. Its latin name is Xanthium canadense or X. commune and the form referred to is named by Mr. Cockerell X. Wootoni, in honour of Professor E. O. Wooton who described the first collected specimens.

Xanthium barcinonense Sennen, Bull. Gogr. Bot. 24(Nos. 295297): 224 (1914). Type/s: é–‘Hab.Catalogne: Barcelone Can Tunis et la Farola; Prat del Llobregat. Syntypes: ?

Xanthium globosum C. Shull, Bot. Gaz. 59: 482 (1915). Type: not cited. Note: Shull noted earlier in the discussion that this variety was first seen on the Campus of the State University of Kentucky several years ago. It has been found to breed true Note: there is a duplicate of material cultivated from the type donated to K by Sherff.

Xanthium pennsylvanicum Gand., Bull. Soc. Bot. France 65: 54 (1918), nom. illegit. non Wallr. (1844). [Type: Hab.: America bor., Pensylvania Delaware ad Darby Creek (Mac Elwee n. 1316!).]

Xanthium leptocarpum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 3 (1918). Type: L. R. Jones, Burlington, Vermont, September 12, 1896 (type in Herb. Field Museum, cat. no. 430860). Holotype: F.

Xanthium arcuatum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 4 (1918). Type: T.F. Lucy, river shores and low places, Chemung County, New York, October 11, 1896 (type in Herb. Field Museum, cat. no. 4953). Holotype: F.

Xanthium cylindricum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 4 (1918). Type: J.K. Small and A. M. Huger, Chimney Rock to Hendersonville, North Carolina, October 3, 1901 (type in Herb. Field Museum, cat. no. 401312). Holotype: F.

Xanthium acutilobum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 6 (1918). Type: J. Reverchon, Oak Cliff, Texas, September 2 (type in Herb. Missouri Botanical Garden no. 85603; duplicate sheets in the same herbarium bear the numbers 85470 and 85485). Holotype: MO; isotypes: MO 2.

Xanthium crassifolium Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(1): 5 (1918). Type: בB. Mackensen 123, San Antonio, Texas, October 8 and November 15, 1911 (type in Herb. Field Museum, cat. no. 324122). Holotype: F.

Xanthium curvescens Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser. 4(2): 25 (1919). Type: Vermont: Orwell, Willard W. Eggleston 1420 [Sept. 23 1899] (type in Hb. Gray). Holotype: GH; isotype: US.

Xanthium cenchroides Millsp. & Sherff., Publ. Field Mus. Nat. Hist., Bot. Ser. 4(2) : 30 (1919). Type: Texas: near Ferris, J. Reverchon 2332 (type in Hb. Mo. 85563; additional material, ibid., on sheet no. 85564). Holotype: MO; isotype: MO.

Xanthium calvum Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser., 4: 35 (1919). Type: California: vicin. of Palo Alto, foothills, [near Stanford Univ. Col.] C.F.Baker 1760 [2.3.13] (Hb. Calif. 131236, type: Hb. Field 226601; Hb. Gray; Hb. Mo. 85385; Hb. N.Y.). Holotype: AHUC?; isotypes: F, GH, MO, NY, US.

Xanthium australe Millsp. & Sherff, Publ. Field Mus. Nat. Hist., Bot. Ser., 4(2): 37 (1919). Type: [Mexico:] Tamaulipas: vicin. of La Barra, 8 km. east of Tampico, at sea-level, Dr. Edward Palmer 275. Holotype: US (463216).

Xanthium japonicum Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 31 (1923). Types: From the Herb. of the Royal Gardens, Kew, Oldham, No. 409. Nagasaki (Oldham, Hb. Leyd., Berl., Hofm., Gtt.) Japonia (Buerger, Hb. Leyd.) Japonia (T.?, Hb. Leyd.).í¸™í¶’ Syntype: Oldham 409, GOET.

Xanthium sibiricum Patrin ex Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 32 (1923). Types: Under the heading of Exsiccaten Widder listed Herbarium of the late East India Company, Nr. 3183. Herbarium Schlagintweit from India and High Asia, Nr. 720, 4360. Henrys Collection from Central China 188588, Nr. 51. Schindler, Plantae sinenses, Nr. 205, 212. Bohnhof, Voyage au lac Hanka et en Mandchourie, Nr. 200. Cavalerie, Plantes de Chine, Nr. 3814. Erbario Biondi, Nr. 299. Widder also listed many more specimens under Gesehene Pflanzen.

Xanthium sibiricum Patrin ex Widder var. subinerme (C. Winkler) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 34, 36 (1923).

Xanthium strumarium L. var. hausmanni Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 49 (1923). Type: Von Bedeutung ist eine Form, die von Hausmann mehrmals zwischen Bozen und Salurn in Sdtirol gefunden wurde.

Xanthium pungens Wallr. var. denudatum Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 69 (1923). Type: ich nur in einem Exemplar von Kansas, Atchison Co. im Hb. U. W. (leg. Hitchcock). Die Exemplare derselben Nummer (727) desselben Exsiccatenwerkes, die im Hb. Wash. liegen, sin normales X. pungens.

Xanthium decalvatum Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 72 (1923). Type: å’‘Herbarium of the U. S. Exploring Expedition under the command of Capt. Wilkes, Nr. 1361 (als X. strumarium var. canadense bezeichnet!). Holotype: US. Note: See also comments under X. campestre Greene, which indicated this is the type of that name also.

Xanthium orientale L. forma laciniatum (Pouzolz) Thell. ex Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 80 (1923).

Xanthium italicum Moretti var. albinum Widder, Feddes Repert. Spec. Nov. Regni Veg. Beih. 20: 105 (1923). Type: Im Elbetal und dessen nherer Umgebung kommen jedoch fast ausschlie lich Formen mit etwas dicklichen, eifmigen,

Xanthium californicum Greene var. oligacanthum (Piper) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 112 (1923).

Xanthium pungens Wallr. var. globosum (C. Shull) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 166 (1923).

Xanthium pungens Wallr. var. cylindricum (Millsp. & Sherff) Widder, Feddes Repert. Spec. Nov. Regni Veg., Beih. 20: 167 (1923).

Xanthium saccharatum Wallr. ssp. commune (Britton) Widder, Feddes Repert. Spec. Nov. Regni Veg. 21(8í·•í²–20): 286 (1925).

Xanthium saccharatum Wallr. ssp. aciculare Widder, Feddes Repert. Spec. Nov. Regni Veg. 21(820): 286 (1925). Type: not cited, but many, many syntypes appear to have been cited.

Xanthium chinense Mill. var. globuliforme C. Shull, Bot. Gaz. 83(4): 385 (1927). Type: Cult. material from Mr. F. F. Crevecoeur near Onaga, Kansas in summer of 1909.

Xanthium aridum St. John, Northwest Sci. 2(3): 93, fig. 4 (1928). Type: [U.S.A.: Washington. Gravel benches in Black Canyon, Rattlesnake Hills, 2400 ft. alt. St. John et al. 8100, April 8, 1927] Isotype: US.

Xanthium pennsylvanicum Gand. var. laciniatum C. Shull & Sherff, Bot. Gaz. 92: 208 (1931). Type: Earl E. Sherff 5012, cultivated in experimental garden of University of Chicago, Chicago, Illinois, Oct. 11, 1930. Holotype: F; isotypes: K, US. [Note: This material originated in a clump on loam soil at one end of a corn field belonging to Mr. Crevecouer, near Onaga, Kansas, July 19, 1928. Burs from the Crevecouer material were planted by Dr Shell in the summer of 1930 ]

Xanthium mongolicum Kitag., Rep. First Sc. Exped. Manchoukuo, Sect. 4, 4: (Index Fl. Jehol.): 97 (1936). Type: Hab. Manshuria: Prov. Hsing-an occid. []: In arenosis circa collis Szu-lng-tzu-shan [ê––] prope O-ny-to [æ––] (N.H.K. Oct. 2. 1933 Typus). Dist. Manshuria. Holotype: ?

Xanthium natalense Widder, Feddes Repert. Spec. Nov. Regni Veg. 41: 274 (1937). Type: Natal, near Durban, alt. 100'; I. 1902 (J. Medley Wood, NG n. 8943 = Urbeleg = Typus).

Xanthium strumarium L. var. glabratum (DC.) Cronquist, Rhodora 47: 403 (1945).

Xanthium chasei Fernald, Rhodora 48: 66 (1946). Type: [USA:] Illinois: bottomlands of Illinois Ruver near Peoria , Sept. 15, 1945, Chase, no. 8205. Holotype: GH; isotype: in herb. Chase.

Xanthium strumarium L. var. japonicum (Widder) Hara, Enum. Sperm. Jap. 2: 279 (1952).

Xanthium strumarium L. ssp. cavanillesii (Schouw) D. Lve & Dans., Canad. J. Bot. 37(): 205 (1959).

Xanthium albinum (Widder) Scholz & Sukopp, Verh. Bot. Vereins Brandenb. 98-100: 47 (1960)

Xanthium ripicola J. Holub, Folia Geobot. Phytotax., 11(1): 83 (1976), nom. nov. pro X. riparium Lasche, non X. riparium Itzigs. & Hertsch (1854) (nom. illegit.).

Xanthium orientale L. var. albinum (Widder) Adema & M. T. Jansen, Gorteria 9(9): 302 (1979).

Xanthium orientale L. var. riparium (Itzigs. & Hertsch) Adema & M. T. Jansen, Gorteria, 9(9): 303 (1979).

Xanthium strumarium L. var. wootonii (Cockerell) W. C. Martin & C. R. Hutchins, Fl. New Mexico, 2: 2041 (1981), nom. inval. (without basionym ref.)

Xanthium albinum (Widder) H. Scholz ssp. ripicola (Holub) J. Dostal, Folia Mus. Rer. Nat. Bohem. Occid., Bot., 21: 12 (1984).

Xanthium strumarium L. forma purpurascens S. Priszter, Magyar Fl. Veg. 7: 58 (1985). Type: Praematricum: Kunbaracs, 1972. HHBp.

Xanthium strumarium L. ssp. brasilicum (Vell.) O. Bol s & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988].

Xanthium echinatum Murray ssp. italicum (Moretti) O. Bols & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988].

Xanthium echinatum Murray var. italicum (Moretti) O. Bol s & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988].

Xanthium echinatum Murray var. cavanillesii (Schouw) O. Bols & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988].

Xanthium cloessplateaum D. Z. Ma, Acta Bot. Bor.-Occid. Sin. 11(4): 346 (1991). Type: Ningxia: Tongxing, IX.1984. leg. X. Z. Dong. No. 424. Holotype: ò‘’‘Ningxia Agr. Col. Conserv.

Xanthium sibiricum Patrin ex Widder var. jingyuanense H. G. Hou & Y. T. Lu Bull. Bot. Res., Harbin 20(3): 249 (2000). Type: China. Gansu, Jimgyan, Hongzuizi, alt. 1450 m, riverside, 1998-08-26, H.G. Hou and Y. T. Lu 98018. Holotype: Herb. LanZhou University; isotype: PE.

Xanthium strumarium L. ssp. sibiricum (Patrin ex Widder) Greuter, Willdenowia 33(2): 249 (2003).

This is a very widespread species, in many warm temperate and subtropical countries, and is perhaps only truly native in Europe having been recorded in the mid-1500s. Widespread in eastern, central and southern Europe. Argentina, Australia, Azores, Bolivia (Santa Cruz), Brazil, Egypt, Hawaii, Iraq, Japan, Mascarenes, Mexico, New Zealand, Russia, Sri Lanka, Turkey, West Indies.

Abrojo, Aborojo grande, Abrojo macho, Cadillo, Maleza (Freire et al., 2006).

Xanthium strumarium L. var. arenarium (Lasch) Uechtritz, Verh. Bot. Vereins. Prov. Brandenburg 34: 210 (1862) = Xanthium strumarium L.

Xanthium strumarium L. ssp. brasilicum (Vell.) O. Bols & J. Vigo, Collect. Bot., 17(1): 90 (1987)[1988] = Xanthium strumarium L.

Xanthium strumarium L. var. canadense (Mill.) Torr. & A. Gray, Fl. N. Amer. 2: 294 (1841-43) = Xanthium strumarium L.

Xanthium strumarium L. ssp. cavanillesii (Schouw) D. L ve & Dans., Canad. J. Bot. 37(): 205 (1959) = Xanthium strumarium L.

Xanthium strumarium L. var. glabratum (DC.) Cronquist, Rhodora 47: 403 (1945) = Xanthium strumarium L.

Xanthium strumarium L. var. hausmanni Widder, Feddes Repert. Spec. Nov. Regni Veg. 20: 49 (1923) = Xanthium strumarium L.

Xanthium strumarium L. var. japonicum (Widder) Hara, Enum. Sperm. Jap. 2: 279 (1952) = Xanthium strumarium L.

Xanthium strumarium L. forma purpurascens S. Priszter, Magyar Fl. Veg. 7: 58 (1985) = Xanthium strumarium L.

Xanthium strumarium L. ssp. sibiricum (Patrin ex Widder) Greuter, Willdenowia 33(2): 249 (2003) = Xanthium strumarium L.

Xanthium strumarium L. var. wootonii (Cockerell) W. C. Martin & C. R. Hutchins, Fl. New Mexico, 2: 2041 (1981), nom. inval. (without basionym ref.) = Xanthium strumarium L.

Xanthium varians Greene, Pittonia 4: 59 (1899) = Xanthium strumarium L.

Xanthium wootoni Cockerell ex De Vries, Sp. Var. : 140 (1905) = Xanthium strumarium L.

Xanthium xanthocarpon Wallr., Beitr. Bot. 1(2): 241 (1844) = Xanthium spinosum L.

Xenophontia caryophylla Vell., Fl. Flum. : 347 (1825)[7 Sept. - 28 Nov. 1829] = Barnadesia caryophylla (Vell.) S. F. Blake