568 
48 . AMBROSIACEiE. 
Coarse weedy lierbs with inconspicuous fl. and no peculiar pro- 
perties or uses. 
tfl. Xanthium. Male anthodia many-fid. ; scales of inv. 
in a single row, free ; recept. chaffy. Fem. anthodia 2-JUl ., 
cor. tabular-Jiliform. Ach. 2 enclosed in the thickened 
indurated 2-celled inv. which is shortly 2-beaked and 
clothed with hook-tipped spines. — Erect branched herbs 
with coarse rough angular or lobed 1. 
tf2. Ambrosia. Male anthodia many-fld. ; scales of inv. 
more or less concrete or combined into a shallow cup ; re- 
cept. naked. Fem. anthodia 1-fld., cor. 0. Ach. single 
enclosed in the persistent inv. which is 2-beaked and en- 
circled with a ring or coronet of short straight spines or 
points. — Erect herbs with divided compound pinnatisect 1. 
tfl. Xanthium L. 
tfl. x. STRUM ARIUM L. Burr- weed. 
Unarmed ; 1. pedately nerved triangularly cordate irregularly 
angulato-lobed and toothed, shortly cuneate at the base and 
cut away to the two outer lateral nerves ; heads crowded sub- 
sessile in short terminal or axillary more or less stalked rac., 
the male heads above the female ; fr. erect or erecto-patent 
obovoidal or obovate attenuate at the base, shortly pubescent, 
beaks straight simple not hook -tipped, spines slender straight 
hooked at the tip and the length of half the diam. of the fr. — 
Linn. Sp. 1400; Yill. Dauph. iii. 68; Lam. Diet. iii. 412; 111. 
t. 705. fr. 1, 2; Desf. ii. 343; Brot. i. 480; Pers. ii. 558; Buch 
195. no. 272; E15. t. 2544; Sm. E. Fl. iv. 130; DU. v. 628; 
WB. ii. 241 ; Koch 531 ; Coss. et Germ. ii. 444; Bab. 208 ; 
Gren. et Godr. ii. 393; 11FG. xix. 101, t. 215. f. ii. — Herb. aim. 
Mad. reg. 1, 2, r. Machico, roadsides and waste ground at the 
back of the beach ; Terra Chao above P t0 Moniz, roadsides and 
cornfields; “ P ta Delgada on the S. Vicente road," Dr. Lip- 
pold. July-Sept. — An erect branched shortlv furry-pubescent 
dull gr. pi. 1-2 ft. high, with somewhat the habit or aspect of 
Chenopodium Bonus Henricus L. St. ribbed and angular, flexu- 
ous upwards, often dark reddish-brown. L. on long petioles 
about as long as themselves, angularly coarsely and irregularly 
lobed and toothed, 3-4 in. long and nearly or quite as broad at 
the base, subcordate shortly acuminate, soft flaccid and fast 
withering, strigosely rough or scabrous above, nearly smooth 
and paler beneath, pedately 3 or 5- nerved and cut away at the 
base to the 2 outer nerves as in Lappa minor. Pac. short 
tlexuous; male heads superior rather numerous (10-15) glo- 
bose or oval about 2 lines in diam., their inv. inconspicuous : 
fem. fl. fewer at the base of the rac. Fr. burr-like very hard 
