GERTNERIA COMPOSIT 2 337 
‘XANTHIUM 
Nutt. Stems 1-3 feet high, from an annual or biennial root, diffusely 
branched from the base, hirsute-pubescent or hispid, sometimes canescent 
with strigose-sericeous pubescence when young: leaves of ova'e or round- 
ish outline, 1-3 inches broad bipinnatifid or the upper oblong and only 
pinnatifid: staminate racemes solitary or paniculate: pistillate involucres 
armed with flat and thin lanceolate-subulate smoo’h and glabrous long 
and straight spines, 3-4 lines long, commonly 1-flowered. On sandy plains 
and river-banks, Brit. Columbia to California and Nevada. 
G. bipinnatifida O. Ktz. Rev. Gen. i, 339. Franseria bipinnatifida Nutt. 
Herbaceous perennial with stout procumbent stems 2-3 feet long, some- 
what hirsute : leaves ovate in outline, 1-2 inches long, 2-3-pinnately parted 
into oblong-linear divisions and sma'l oblong lobes, canescent with soft 
tomentum or fine hirsute-sericeous pubes.ence: staminate heads rather 
large, in dense spikes or racemes; pistillate heads ovate-fusiform, armed 
with rather short and thick but flattish tubercle-like spines, their acute 
tips sometimes incurving. On sandy beaches along the coast, Brit. Colum- 
bia to California. 
G. Chamissonis O. Ktz.1].c. Franseria Chamissonis Less. Stems pro- 
cumbent, 2-3 feet long, from a perennial root: leaves cuneate-obovate or 
oblong-ovate with a cuneate base, 3-5-nerved at base, obtusely serrate, the 
lower often Jaciniate-incised : staminate spikes or racemes dense, of rather 
large heads; pistillate heads ovate, armed with rather short and tick but 
flattish canalicu'ate tubercule-like spines. Sandy sea-beaches, Brit- Co- 
lumb a to California. Not common. 
* * Involucre of the staminate heads of few distinct bracts Re- 
ceqtacle cylindraceous. 
XANTHIUM Tourn. L. Gen. n. 1056- (cocKLE-BUR) 
Coarse annuals with branching stems, alternate and usually 
lobed or toothed leaves, and mostly clustered heads of greenish 
or yellowish flowers, in terminal or larger axillary clusters of 
both sexes, the staminate uppermost. Involucre of the globu- 
lar sterile heads 1-2 series of small narrow bracts. Receptacle 
distinctly paleaceous, a cuneate or linear-spatulate chatty bract 
partly enclosing each sterile flower. Filaments monadelphous. 
Anthers distinct but connivent, the inflexed apical appendage 
mucronate. Sterile styleunappendaged. Fertile head a closed 
and ovoid bur-like 2-celled and 2-flowered involucre, 1-2-beak- 
ed at the apex, the surface clothed with uncinate-tipped prickles: 
each flower a single pistil, maturing a thick ovoid achene, the 
two permanently enclosed in the indurated prickly involucre. 
-* Leaves cordate or ovate, 3-ribbed from the base, with dentate 
margins, and often incised or lobed, on long petioles: axiles unarmed : 
fruiting invyolucre with 2 prominent beaks. 
X. strumarium L. Sp. 987. Rough: stems1-6 feet high: leaves slender- 
petioled, broadly ovate to orbicular, 3-ribbed and more or less cordate at 
base, the lower often 10 inches broad, irregularly dentate and more or 
less 2-5-lobed: fruitiug involucre 6-9 lines long, glabrous or pubernlent; 
the beaks straight and rarely at all hooked at maturity. In waste places. 
Naturalized from Europe. 
X. Canadense Mill. Dict. ed. 8, No 2. Stems stout, 1-2 feet high, often 
punctate with brown spots: leaves ample, broadly ovate, coarsely and irreg- 
