Xanthium orientale subsp. italicum (Moretti) Greuter

Xanthium italicum Moretti, Giorn. Fis. II. 5: 326. 1822
Xanthium varians Greene, Pittonia 4: 59. 1899. Xanthium glandulifcrum Greene. Pittonia 4: 61. 1899. Xanthium commune Britton, Man. 912. 1901. Xanthium Macounii Britton, Man. 913. 1901.
Stems branched, scabrous, often lengthwise-punctate with dark-purple linear dots, 3-10 (-18) dm. high; leaves 0.8-3 dm. long including the petioles; petioles nearly equaling or even exceeding the blades; blades cordate or widely ovate, lobed, dentate, scabrous; body of the fruit cylindric, oblong or ovoid, but more often broadly oblong, glandular-pubescent, 1.3-1.8 cm. long, 6-8 mm. thick; beaks commonly incurved and hooked at the apex, hispid, 5-7 mm. long; prickles commonly numerous and slender ('rarely either sub-remote or rather thick), hispid from the base up to the middle, glabrous above, hooked at the apex, 3-7 mm. long.
TypB locality: Italy.
I DISTRIBUTION: Quebec to West Virginia, Saskatchewan, Washington, and California; Oaxaca; also in Europe.

Xanthium australe Milisp. & Sherff, Field Mus. Publ. Bot
4: 37. 1919.
Stem scabrous, more or less punctate lengthwise with small linear spots, probably 0.5-1 m. high; leaves 0.8-2 dm. long including the petioles; petioles and blades about equal; blades petiolate, 3-nerved, deltoid-cordate, often obscurely lobed, dentate, scabrous; body of the fruit ovoid-subglobose, somewhat sparsely glandular-pubescent or glabrate, 0.9-1.1 cm. long and 6-7 mm. thick (or even 1.3-1.5 cm. long and 8-9 mm. thick on a Chilean specimen) ; beaks attenuate, straight or slightly inflexed, hooked or almost straight at the apex, pubescent below, 6-9 mm. long; prickles crowded, slender, straight or slightly arcuate, shortly and somewhat sparsely pubescent below (a specimen from Chile has certain prickles glandular and not pubescent), glabrous above, hooked at the apex, 4-5 mm. long.
Type locality: Vicinity of La Barra, 8 kilometers east of Tampico, Tamaulipas.
Distribution: Mexico; also in Paraguay and Chile.