1. C. Virginiànum, L. Usually low (2--15´ high); leaves ovate, mostly obtuse, crenate, rarely somewhat cordate, or the radical obovate with cuneate base; rays ½´ long.--Dry soil, from southern Penn. to Fla. May--Aug.--Var. DENTÀTUM, Gray; leaves deltoid-ovate, acute, coarsely dentate-serrate; involucral scales more acute.--High Island at the Falls of the Potomac. 40. ENGELMÁNNIA, Torr. & Gray. Heads and flowers of the preceding genera. Rays 8--10. Involucre of about 10 outer loose foliaceous scales, more or less dilated and coriaceous at base, and several firm-coriaceous, oval or obovate, concave inner ones with short abrupt green tips. Chaff of the flat receptacle firm and persistent. Achenes flat, obovate, wingless, tardily deciduous with the attached scale and chaff; pappus a firm scarious hispid crown, more or less lobed.--A coarse hispid perennial, with alternate deeply pinnatifid leaves, and somewhat paniculately disposed heads on slender naked peduncles; flowers yellow. (Named for the eminent botanist, _Dr. George Engelmann_.) 1. E. pinnatífida, Torr. & Gray. Stems 1--2° high; heads ½´ broad, and rays ½´ long.--Central Kan. to La., and westward. 41. PARTHÈNIUM, L. Heads many-flowered, inconspicuously radiate; ray-flowers 5, with very short and broad obcordate ligules not projecting beyond the woolly disk, pistillate and fertile; disk-flowers staminate with imperfect styles, sterile. Involucre hemispherical, of 2 ranks of short ovate or roundish scales. Receptacle conical, chaffy. Achenes only in the ray, obcompressed, surrounded by a slender callous margin, crowned with the persistent ray-corolla and a pappus of 2 small chaffy scales.--Leaves alternate. Heads small, corymbed; the flowers whitish. (An ancient name of some plant, from παρθένος, _virgin_.) 1. P. integrifòlium, L. Rough-pubescent perennial (1--3° high); leaves oblong or ovate, crenate-toothed, or the lower (3--6´ long) cut-lobed below the middle; heads many in a very dense flat corymb.--Dry soil, Md. to Ill., Minn., and southward. June--Aug. 42. ÌVA, L. MARSH ELDER. HIGHWATER-SHRUB. Heads several flowered, not radiate; the pistillate fertile and the staminate sterile flowers in the same heads, the former few (1--5) and marginal, with a small tubular or no corolla; the latter with a funnel-form 5-toothed corolla. Anthers nearly separate. Scales of the involucre few, roundish. Receptacle small, with narrow chaff among the flowers. Achenes obovoid or lenticular, pappus none.--Herbaceous or shrubby coarse plants, with thickish leaves, the lower opposite, and small nodding greenish-white heads of flowers; in summer and autumn. (Name of unknown derivation.) § 1. _Heads spicate or racemose in the axils of leaves or leaf-like bracts; fertile flowers with evident corolla._