346 COMPOSITE. Franserui. 



Southeastern borders of the State : eastern slope of Providence Mountains, Cooper. On the 

 Colorado, Newberry. iMuiting involucre in the si)eciniens examined one-celled and one-seeded. 



§ 2. Fertile involucre mostli/ 2-rclled and 2-Jhwered, small, armed tvith short and 

 stoat incurved hook-tipped spines : leaves dissected. 



8. F. tenuifolia, ^!niy. Herbaceous, iippavcntly j)uromiial : Hteiii orucl, 1 to 3 

 feet high, hirsuLu : leaves twice or thrice piiinatilid or dissected, strigosely pubescent 

 or hirsute, or sometimes even canescent beneath ; tlie ultimate divisions linear ; 

 small lobes often interposed on the rhachis : sterile spLkes simple aud elongated or 

 paniculate : fertile involucres glomerate, at maturity only one or two lines long, 

 ovoid or globular, minutely pubescent : its short and stout subulate spines more or 

 less incurved and with uncinate tips. — PI. Fendl. 80 ; 1*1. Wright., &c. 



Southciiatorn liordcrij of the Stiitc, thonco eastward to the Gulf of Mexico; also in the Sand- 

 wich Islands, and in Lower California, Cape San Lucas, Xantiis. Doubtless it is also F. hispida, 

 Beuth. Bot. Sulph. (although that is said to have sometimes four Howors in the involucre) : but 

 the present name will still hold, as Ambrosia tenuij'olia, Sjjreng., is, it appears, the very same 

 species. 



§ 3. Fertile involucre 2 - i-celled, 2 - A-Jlowered, thickly beset (like Xanthium) xvith 

 slender and rather soft hook-tipj)ed prickles. 



9. F. ambrosioides, Cav. Tall, 4 to 6 feet high, with a woody base, hirsute- 

 pubescent: leaves oblung-iunceolate with mostly truncate or conlate base, acuminate, 

 unequally toothed, 3 to 5 inches long, tiio petiole sometimes wing-ap[)endaged at 

 base : sterile raceme rather loose : fruiting involucre lialf an incli long, minutely 

 hispid. 



Occurs near the southeastern and the southern frontiei-s of the State, and probably within its 

 limits. Not rare in Mexico. 



42. XANTHIUM, Touni. Cocklebuii, Clothur. 



Heads homogamous and unisexual, niona>cious, in axillary or terminal clusters 

 or short interrupted s[iike3; the pistillate 2-llowered and underneath the several- 

 flowered staminate. IStaminate Uowers as in Ambrosia, except that the involucre is 

 of several distinct and narrow scales, and the receptacle more or less elevated, its 

 chaff broader. Pistillate flowera enclosed in a bur-like ovoid or oblong closed 

 indurated involucre, which is 2-celled, 2-flowered, and armed all over with strong- 

 ly hook-tipped prickles : corolla none. Akenes obovoid, thick : pappus none. — 

 Coarse and vile annual weeds, with alternate petioled leaves ; the three or four 

 species perhaps all natives of America, but now widely dispersed over the world ; 

 probably none indigenous to California. 



1. X. stnimarium, Linn. Stems a foot or two high, not prickly : leaves del- 

 toid-ovate or somewhat cordate, irregularly serrate, often slightly incised, rough and 

 green both sides, on long petioles : fruiting involucre over half an inch long, thick, 

 tipped with a pair of strong beaks, pubescent or sometimes hispid between and on 

 the lower {)art of the crowded prickles. 



Waste grounil near dwellings, &c. ; also on the sea-const. The common Cocklcbur, npymrcntly 

 less conunon than nt the east ; but botli the ordinary form occurs and var. ec/iinatum, Torr. k 

 Gray, with thicker and glandular-hispid involucre. 



2. X. spinosum, Linn. Hoary-pubescent : stems much branched, bearing long 

 and yellowish triple spines by the side of the leaves : these lanceolate or ovate- 

 lanceolate, canescent beneath, often 2 - 3-lobed or cut, tapering into a short petiole : 

 fruiting involucre narrow, half an inch or less long, more sparsely prickly, the beak 

 inconspicuous. 



Sea-coast, San Juan, &c. ; also in the IVwt-hills, Calaveras Co.: introduced from Chili. 



