_Flowers in a close head_ (the compound flower of the older botanists), _on a common receptacle, surrounded by an involucre, with 5 (rarely 4) stamens inserted on the corolla, their anthers united in a tube (syngenesious)._--Calyx-tube united with the 1-celled ovary, the limb (called a _pappus_) crowning its summit in the form of bristles, awns, scales, teeth, etc., or cup-shaped, or else entirely absent. Corolla either strap-shaped or tubular; in the latter chiefly 5-lobed, valvate in the bud, the veins bordering the margins of the lobes. Style 2-cleft at the apex (in sterile flowers usually entire). Fruit seed-like (_achene_), dry, containing a single erect anatropous seed, with no albumen.--An immense family, in temperate regions chiefly herbs, without stipules, with perfect, polygamous, monœcious or diœcious flowers. The flowers with a strap-shaped (_ligulate_) corolla are called _rays_ or _ray-flowers_; the head which presents such flowers, either throughout or at the margin, is _radiate_. The tubular flowers compose the _disk_; and a head which has no ray-flowers is said to be _discoid_. When the head contains two sorts of flowers it is said to be _heterogamous_; when only one sort, _homogamous_. The leaves of the involucre, of whatever form or texture, are termed _scales_. The bracts or scales, which often grow on the receptacle among the flowers, are called the _chaff_; when these are wanting, the receptacle is said to be _naked_.--The largest order of Phænogamous plants. The genera are divided by the corolla into three series, only two of which are represented in the Northern United States. The first is much the larger. Systematic Synopsis. SERIES I. TUBULIFLORÆ. Corolla tubular in all the perfect flowers, regularly 5- (rarely 3--4-) lobed, ligulate only in the marginal or ray-flowers, which when present are either pistillate only, or neutral (with neither stamens nor pistil). Tribe I. VERNONIACEÆ. Heads discoid; the flowers all alike, perfect and tubular, never yellow. Branches of the style long and slender, terete, thread-shaped, minutely bristly-hairy all over.--Leaves alternate or scattered. 1. Elephantopus. Heads 3--5-flowered, several crowded together into a compound head. Involucre of 8 scales. Pappus of several chaffy bristles. 2. Vernonia. Heads several--many-flowered, separate. Involucre of many scales. Pappus double, the inner capillary, the outer of minute chaffy bristles. Tribe II. EUPATORIACEÆ. Heads discoid, the flowers all alike, perfect and tubular, never yellow. Branches of the style thickened upward or club-shaped, obtuse, very minutely and uniformly pubescent; the stigmatic lines indistinct. [*] Pappus a row of hard scales. 3. Sclerolepis. Head many-flowered. Scales of the involucre equal. Leaves whorled. [*][*] Pappus of slender bristles. [+] Achene 5-angled; bristles of the pappus roughish. 4. Mikania. Flowers and involucral scales only 4. Stems twining.