NORTH AMERICAN FLORA [VOLUME 33 
to 
bo 
of the lower leaves orbicular in outline, 1-2 dm. long, the upper rhombic or ovate; divisions 
often 2—3-lobed, ovate, toothed; staminate heads numerous, in terminal racemes or panicles; 
involucre saucer-shaped, 3 mm. broad, with 3 dark ribs on the upper side and hispidulous on 
the portion between these ribs, otherwise glabrous, with 6-8 rounded lobes; paleae of the re- 
ceptacle rudimentary; corolla glabrous, with 2 or more of the angles dark-colored; pistillate 
heads in small clusters on the lower part of the racemes, subtended by linear leaves or some- 
times by partly united involucral bracts; body of the fruit obovoid, about 4mm. long, with 4-8 
obtuse ridges and pitted in the intervals, with as many small or obsolete tubercles; beak conic, 
1 mm. long. 
TYPE LOCALITY: ‘‘Near Bejar, Mexico”? [now Bexar, Texas]. 
DISTRIBUTION: Lousiana and Mississippi to Arizona, Sonora, and Chihuahua. 
21. Ambrosia cheiranthifolia A. Gray, Bot. Mex. Bound. Surv. 
Sipe Meoee 
A perennial herb; stem about 3 dm. high, terete, grayish-strigose; leaves mostly opposite, 
entire and entire-margined, sessile, oblanceolate or oblong-lanceolate, finely and densely gray- 
ish-strigose on both sides, 2-4 cm. long; staminate heads rather few in terminal racemes; in- 
volucre saucer-shaped, about 4 mm. wide, canescent, with 5-6 triangular acute lobes; paleae 
of the receptacle linear or oblanceolate, 1-nerved, ciliate towards the apex; corolla slightly 
puberulent with dark-colored angles; pistillate heads in small clusters in the upper axils; fruit 
puberulent, somewhat angled, obovoid; body about 3 mm. long; beak stout, conic, 1.5 mm. 
long; spines 4-5, conic, more or less spreading, about 1 mm. long. 
TYPE LocALITty: San Fernando, Coahuila. 
DISTRIBUTION: Coahuila. 
10. ACANTHAMBROSIA Rydberg, gen. nov. 
Low shrubs, with alternate, bipinnatifid or tripinnatifid leaves. Staminate heads nod- 
ding in terminal spikes; involucre campanulate, irregularly lobed; paleae of the receptacle fili- 
form; corolla hyaline, tubular-funnelform, glabrous; filaments monadelphous; anthers distinct, 
oblong, with triangular, slightly incurved tips; pistil abortive. Pistillate heads solitary, at 
the base of the staminate spike, erect, 3—5-flowered; involucre turbinate, with a series of 5 
long slender divergent spines near the apex and one 3- or 4-toothed beak. 
Type species, Franseria Bryantit Curran. 
-1. Acanthambrosia Bryantii (Curran) Rydberg. 
Franseria Bryantit Curran, Proc. Calif. Acad. II. 1: 232. 1888. 
A low shrub, with gray or straw-colored bark, divaricately branched; leaves ovate in out- 
line, sparingly strigose, 2-3 cm. long; segments linear or oblong, more or less revolute-mar- 
gined; staminate heads subsessile; involucre campanulate, glandular-granuliferous, his- 
pidulous-ciliate, 2 mm. wide, 3.5 mm. deep, irregularly lobed; lobes broadly triangular; pistil- 
late heads solitary, subsessile; body of the fruit 5-6 mm. long; beak solitary, subulate, 3 mm. 
long; spines terete, subulate, 15-30 mm. long, in age white. 
TYPE LOCALITY: Magdalena Bay, Lower California. 
DISTRIBUTION: Lower California. 
11. FRANSERIA Cav. Ie.'2: 78.  1793- 
Gaertneria Medic. Vorles. Kurpf. Phys.-dkon. Ges. 4: 198. 1789.—Phil. Bot. 1: 45. 1789. 
Not Gaertneria Schreb. 1789. 
Xanthidium Delpino, Studi Lign. Anem. 62. 1871. 
Annual or perennial herbs, or low shrubs, with opposite or alternate, toothed or dissected 
leaves. Staminate heads nodding, spicate or racemose at the end of the branches; involucre 
saucer-shaped or turbinate, lobed, toothed, or crenate; paleae of the receptacle filiform to 
spatulate; corolla funnelform, 5-toothed; filaments monadelphous; anthers distinct, most 
commonly with incurved cuspidate tips; pistil abortive, the stigma peltate, penicillate. Pis- 
tillate heads nut-like, erect; involucre of several fused bracts forming a bur with several or 
