AMBROSIACEAE . 1297 
To rM to peace clasping, all coarsely toothed: sepals about 
nate: corollas yellow, about 3 mm. long; lobes lanceolate: ee 
see pres the peer subulate ids 4-5 mm. long.—Fields and road- 
sides, N Fla. Nat. of S. Am.—Spr.-fall. 
OrpER CARDUALZES-—CanpUAL, ORDER | 
Herbs, shrubs, or rarely trees. Leaves mainly alternate: blades entire, 
toothed, or divided. Flowers perfect, monoecious, or dioecious, few or 
many aggregated on a receptaele and surrounded with an involuere, or 
the involucre rarely obsolete. Calyx one or two rows of bristles, scales, a 
mere border or crown, or obsolete, or wanting. Corolla of several more 
or less united petals, or wanting. Androecium of usually 5 stamens, the 
anthers converging, or united. Gynoecium mostly of 2 united carpels. 
Ovary inferior. Styles or stigmas mostly 2. Fruit an achene. 
Flowers with tubular ee or those of the outer ones prolonged into ligules. 
Sta 
mens distinct, he filaments sometimes united, 
the anthers mele converging about the stigma. Fam.1. AMBROSIACEAE. 
St 2 united by their anthers, thus forming a tube 
ound the stigma, except in Kuhnia. Fam. 2. 
Flow e with each corolla PEOISBEGR into a ligule. Fain. 3. CICHORIACEAE. 
Panir 1. AMBROSIACEAE — RAGWEED FAMILY 
Annual or perennial herbs, or shrubs, e plan ts often coarse. Lea f- 
blades entire, toothed, lobed, ided. "Flowers in inco nspicuous viden 
the braets of the pistillate heads distinct or sometimes united and accres- 
cent drin a bur. Fruit-producing flowers e or i much reduced 
corollas. Achenes subtended by or enclosed in an involucre. Pappu 
wanting or obsolete.—Eight genera and about 75 species, mostly rel 
Staminate and pistillate flowers in the same head, the pistillate marginal, fewer 
than the staminate, or rarely wanting: heads neither bur- 
ike nor nut-like Tribe I. IvEAE. 
PE m pistillate flowers in different heads, the pistil- 
ate flowers 1—7, enclosed in a bur-like or nut- like involucre, 
Sich A V. encloses the achenes. , II. AMBROSIEAE. 
I. IvE 
Plants with DIESE Bone nodding heads. dud broad or 
narrow leaf-blades 1. Iva. 
II. AMBROSIEAE 
Bracts of the staminate involucre more or less united: 
ceptacle flat or merely convex: filaments free. 
Tubercles or spines of the pistillate involucres in 
single series: fruit with a truncate or equally 3- 5- 
toothed beak. 2. AMBROSIA. 
Tubercles or spines in several series: fruit with a 
p i e beak, the teeth incurved, the outer one the 
3. FRANSERIA. 
Biete M the st aminate ere distinct: receptacle 
elongate filaments uni 
Leaves pinnately i o bed: the stipules simple or 
pronged stipular spines: bur with straight beaks. 4. ACANTHOXANTHIUM. 
Leaves digitately Seded or lobed, the stipules not 
spiny: bur with curved or hooked beaks. 5. XANTHIUM. 
1. IVA L. Annual or perennial, glabrous, strigose, or hispidulous herbs, 
or shrubs. Leaves, at least the lower, opposite: blades entire or toothed. eads 
axillary to leaf-like bracts. Involuere turbinate to hemispheric: bracts 3-6, 
