This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Pubescent or glabrous herbs, or some tropical species shrubby, with alternate dentate leaves, and small heads of tubular flowers in terminal corymbose cymes. Involucre ovoid, campanulate, or nearly hemispheric, its bracts appressed, herbaceous, imbricated in several series. Receptacle flat, naked. Outer flowers of the head pistillate, their corollas filiform, 3-cleft or dentate at the apex. Central flowers perfect, but mainly sterile, their corollas 5-cleft. Anthers sagittate at the base, the auricles caudate. Style of the perfect flowers 2-cleft or. undivided. Achenes 4-5-angled. Pappus a single series of capillary scabrous bristles. [Named for the Abbe N. A. Pluche, of Paris.]
About 35 species, widely distributed in warm and temperate regions. In addition to the following, 2 or 3 other indigenous species occurs in the southern United States, and two introduced ones have been found in waste places in Florida. Type species: Conyza marilandica Michx.
Perennial; leaves sessile, cordate, or clasping at the base.
1. P. foetida.
Annual; leaves, at least those of the stem, petioled.
Leaves short-petioled; heads about 3" high; involucral bracts densely puberulent.
2. P. camphorata.
Leaves slender-petioled; heads 2" -21/2" high; involucral bracts granulose, ciliate.
3. P. petiolata.
Root perennial; stem simple or sparingly branched at the summit, puberulent and slightly viscid, 1 1/2°-3° high. Leaves oblong, ovate or ovate-lanceolate, closely sessile and more or less cordate-clasping at the base, obtuse or acute at the apex, sharply denticulate, pubescent or puberulent, 2'-4' long, 1/2'-1 1/2' wide, reticulate-veiny; clusters of heads sessile, or stalked, compact, leafy-bracted; involucre 2 1/2"-3" high, its bracts lanceolate, acute, viscid-puberulent.
In swamps, southern New Jersey to Florida and Texas, mainly near the coast. Also in the West Indies. Foetid marsh-fleabane. July-Sept.
Erigeron camphoratum L. Sp. Pl. Ed. 2, 1212. 1763. Conyza marilandica Michx. Fl. Bor. Am. 2: 126. 1803. Pluchea camphorata DC. Prodr. 5: 451. 1836.
Root annual; stem usually branched, finely viscid-puberulent, or nearly glabrous, 2°-2° high, somewhat channeled. Leaves ovate, oblong or lanceolate, pu-berulent or glabrous, acute or acuminate at the apex, narrowed at the base, short-petioled, or the upper sessile but not clasping, 3'-8' long, 1'-3' wide, serrate or denticulate, not conspicuously reticulate-veined; heads about 3" high, rarely leafy-bracted, mostly in naked open corymbiform cymes; bracts of the involucre ovate-lanceolate, or lanceolate, acute, puberulent; flowers purplish; achenes pubescent.
In salt marshes, coast of Massachusetts to Florida, Texas and Mexico. Called also ploughman's-wort. Aug.-Oct.
Pluchea petiolata Cass. Dict. Sci. Nat. 42: 2. 1826.
Pluchea foetida DC. Prodr. 5: 452. 1830.
Similar to the preceding species, but glabrate, darker green, usually taller, 21/2°-4° high, the stem stout, rather - strongly channelled. Leaves ovate-lanceolate to oval, thin, 4'-10' long, 1 1/2'-3' wide, mostly acuminate at the apex, cuneate-narrowed at the base, long-petioled, irregularly serrate; petioles of the larger leaves 8"-12" long; heads 2"-2i" high, in terminal and often also axillary clusters; bracts of the involucre granular, cil-iate; achenes short-pubescent.