252 COMPOSITE. Franseria. 



fruiting involucre with single subulate beak as long as the body, the latter bearing about 10 

 rather long rigid subulate-acerose spines, these nearly equalled by the long whitish wool. 

 Proc. Am. A cad. vii. 355, & Bot. Calif, ii. 345. Here also belongs the flowerless specimen 

 coll. by Newberry, mentioned under F. artemisioides in the Colorado Expedition of Ives ; 

 and this is probably the nearest relative of F. chenopodiifolia, Beuth. Arid region, S. E. 

 California and adjacent Nevada, Cooper, Neioberry. Arizona and S. Utah, Parry, Palmer, 

 Lemmon. 



2. Spines of the larger and 2-4- (commonly 3-) flowered involucre very 

 numerous, comparatively slender, and conspicuously uncinate-tipped in the mari- 

 ner of Xanthium. (But the S. American F. artemisioides has stout spines.) - 

 Xanthiopsis. DC. 1. c. 



F. ambrosioid.es, CAV. Shrubby, 4 or 5 feet high, cinereous-pubescent : leaves rather 

 long-petioled, oblong-lanceolate, mostly truncate or subcordate at base, acuminate, irregularly 

 dentate or serrate, 2 to 4 inches long ; petiole naked : fruit ovoid, nearly half-inch and slender 

 prickles 2 Hues long. Ic. ii. 79, t. 200 (excl. syn ) ; Gray, Bot. Calif, i. 346. Xanthidium 

 ainbroxioidcs, Delpino, Stud. -Comp. Artemis. 63. Arizona, Bigclow, Palmer, Pringle, &c. 

 (Lower Calif., Mex.) 



P. ilicifolia, GRAY. Shrubby, at least the branches hirsute, very leafy: leaves rigidly 

 coriaceous, scabrous, reticulate-veiny, sessile, somewhat clasping, oblong-ovate, coarsely den- 

 tate, the teeth and apex spinose: heads ovoid, those seen only 2-celled. Proc. Am. Acad. 

 xi. 77. Canons beyond the southern border of San Diego Co., California, Palmer. Gila 

 Desert, Arizona, Lemmon, foliage only. 



83. XANTHIUM, Tourn. COCKLE-BUR, CLOT-BUR. (Old Greek name 

 of some plant the fruit of which, in the time of Dioscorides, was used to dye the 

 hair 3 r ello\v.) Coarse annuals, chiefly American, of the warmer region, but 

 now widely dispersed weeds ; with branching stems, alternate and usually lobed 

 or toothed leaves, and mostly clustered heads of greenish or yellowish flowers, 

 in terminal and larger axillary clusters of both sexes, the male uppermost ; the 

 lower of few or solitary female heads in axils of leaves : fl. summer and 

 autumn. Gsertn. Fruct. t. 164; Schkuhr, Handb. t. 291; Benth. & Hook. 

 Gen. ii. 355. 



1. Leaves cordate or ovate, 3-ribbed from the base, with dentate margins 

 and often incised or lobed, on long petioles : axils unarmed : fruiting involucre 

 with two prominent indurated beaks. Euxanthium, DC. Prodr. v. 523. Per- 

 haps all derivatives of a single species. 



X. STRUMAKIUM, L. A foot or two high: fruiting involucre half to two-thirds inch long, 

 glabrous or puberulent ; the beaks straight and rarely at all hooked at maturity, and spines 

 rather slender. Spec. ed. 2, ii. 1400; Fl. Dan. t. 270; Schkuhr, Ilaudb. t. 291. A weed 

 of barnyards and in cult, grounds. (Sparingly nat. from Eu. 1 ? or Ind.?) 



X. Canadense, MILL. Stouter: stem often punctate with brown spots: fruiting involucre 

 about an inch long, densely beset with rather long prickles, the stout beaks at maturity 

 usually hooked at the tip or incurved, the surface and base of the prickles more or less hispid, 

 sometimes glabrate. Diet. ed. 8, first after L. Spec. X. majus Canadense, Ilerm. Lugd. 

 635. X. elatius Amcricanum, etc., Moris. Hist. iii. 604, sect. 15, t. 2, fig. 2. X. Carolinensc, 

 etc., Dill. Elth. ii. 432, t. 231. X. orientate, L. 1. c., in part. A'. Amcrlainum, Walt. Car. 

 231. X, mac.rocarptun, var. fjlabratiim, DC. Prodr. 1. c. X. strumariiim, var. Canadense, Torr. 

 & Gray, Fl. ii. 294. Alluvial shores and waste grounds, from Texas to Saskatchewan, 

 Nevada, and California : perhaps extended northward by man's indirect agency. In brackish 

 soil it becomes 



Var. echinatum.. A form, usually dwarf, with still denser and longer prickles, these 

 conspicuously hirsute or hispid. X. echinatum, Murr. Comm. Gcett. vi. 32, t. 4; Torr. & 

 Gray, Fl. ii. 294. X. maculatum, Raf. in Am. Jour. Sci. i. 151. X. macrocarpum, DC. Fl. 

 Fr. Suppl. 356, & Prodr. 1. c. Sandy sea-shores and on the Great Lakes. (S. Am.) 



