Part 1, 1922] AMBROSIACEAE 39 
3. Xanthium chinense Mill. a Dict. ed. 8. Xanthium no. 4. 1768. 
Xanthium occidentale Bertol. Liicubr. Herb. 1822. 
Xanthium macrocarpum glabratum DC. Pode os: 523. 1836. (Ex descr.). 
Xanthium pungens Wallr. Beitr. Bot. 1: 231. 44. 
Xanthium longirostre Wallr. Beitr. Bot. 1: 237. 1844. 
Xanthium carolinense MacM. Metasp. Minn. Valley 535, as synonym. 1892. 
Xanthium canadense Rowlee, Bull. Torrey Club 20: 10. 1893. Not X. canadense Mill. 1768. 
Xanthium strumarium Britton & Brown, Ill. Fl. 3: 298. 1898. Not X. strumarium 1. 1753. 
Xanthium americanum Britt. & Brown, Ill. Fl. ed. 2.3:346. 1913. Not (2?) X. americanum Walt.1788. 
Xanthium glabratum Britton, Man. 912. 1901. 
Xanthium canadense globuliforme Crevecoeur; C. Shull, Am. Jour. Bot. 4: 42. 1917.* 
Stem rough, 0.3-1 (or even —2) m. high; leaves 1-3 dm. long, the lower ones sometimes 
2.5 dm. wide, the petioles and blades subequal; blades widely triangulate-orbicular, acutely 
3—5-lobed, subacutely dentate, cordate or reniform at the base, commonly submembranaceous, 
both sides of the same color and clothed with very short appressed rigid hairs; fruit ovoid or 
fusiform, smoothish, equally and uniformly aculeate, brownish-green or reddish, the body 
very sparsely short-pubescent, glandular, 0.9-1.5 cm. long (rarely longer); beaks straight or 
arcuate, pubescent below, inflexed at the apex or weakly hooked, 3-6 mm. long; prickles gla- 
brate or at the base sparsely glandular-pubescent, straight, hooked at the apex, equalling the 
beaks. 
Type Loca.ity: ‘“‘China.’’ [Veracruz, Mexico] (see Field Mus. Publ. Bot. 4: 21.). 
DISTRIBUTION: Ontario to Massachusetts, Florida, Texas, and California (where very rare); 
eastern Mexico and throughout the West Indies. 
ILLUSTRATIONS: Bull. Torrey Club 20: 10. f. gm Britt. & Brown, Ill. Fl. f. 3599; ed. 2. f. 
4139; Field Mus. Publ. Bot. 3: 87; 4: pl. 7, f. 3; pl. 8, f. 9-15; Britton, Fl. Bermuda. f- FT. 
4. Xanthium cylindricum Millsp. & Sherff, Field Mus Publ. Bot 
4-°4>. “1918. 
Stem scabrid, probably 0.5-1.5 m. high; leaves large, 1.3—2.5 dm. long, the petioles about 
equaling the blades; blades very similar to certain leaves of Hibiscus militaris Cav., subdeltoid- 
ovate, 3-lobed (and almost hastate) or 5-lobed, dentate, cordate or almost truncate at the 
base, membranaceous, scabrous or to the touch almost smooth, clothed with minute appressed 
rigid hairs; body of the fruit cylindric-fusiform, reddish-chestnut in color, dotted with minute 
glands, otherwise glabrous, 1.4-1.6 cm. long and 4-5 mm. thick; beaks arcuate, hooked at the 
apex, glabrate, 4-5 mm. long; prickles slender, reddish, hooked at the apex, glabrate, 2.5-3.5 
mm. long. 
TYPE LOCALITY: Chimney Rock to Hendersonville, North Carolina. 
DISTRIBUTION: North Carolina. 
ILLUSTRATIONS: Field Mus. Publ. Bot. 4: pl. 3; pl. 7, f. 4; pl. 8, f. 16-20. 
5. Xanthium globosum C. Shull, Bot. Gaz. 59: 482. 1915. 
Stem reddish-purple or straw-colored, often purple-punctate with spots running length- 
wise, 3-10 dm. high; branches finally (in robust specimens) more or less elongate, the lowest 
even 1.1 m. long; leaves 0.7—2.3 dm. long, the petioles and blades about equal; blades not con- 
spicuously thick,subdeltoid, 3- or 5-lobed, cordate at the base, serrate, scabrous on both sur- 
faces with minute appressed stiff hairs; fruits often numerous, the body thickly ovoid or sub- 
globose, scarcely pubescent but covered with many very minute glands, 0.9-1.1 cm. long and 
4.5-7 mm. thick; beaks straight or often arcuate, 3-4 mm. long; prickles smooth and straight 
but hooked at the apex, about equaling the beaks. 
TYPE LOCALITY: Lawrence, Kansas. 
DISTRIBUTION: Missouri and Kansas. 
: Ce tae ATIONS: Bot. Gaz. 59: 475-483. f. 1, 4, 5, 7; Field Mus. Publ. Bot. 4: $l. 7, f. SADE 
6. Xanthium arcuatum Millsp. & Sherff, Field Mus. Publ. Bot. 4: 
4. 1918. 
Stem scabrous above, 3-5 dm. high; leaves about 1 dm. long, the petioles and blades 
subequal; blades deltoid-ovate, 3-5-lobed, dentate, cordate or subtruncate at the base, scab- 
* A rare, apparently mutant form occuring in Kansas, with fruits resembling those of X. globosum 
but usually containing 20-30 ovaries. 
