272 COMPOSITJE. (composite family.) 



40. ENGELMANNIA, Torr. & Gray 



Heads and flowers of the preceding genera. Kays 8-10. Involucre ot 

 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 per- 

 ennial, with alternate deeply pinnatifid leaves, and somewhat paniculateh' dis- 

 posed heads on slender naked peduncles; flowers yellow. (Named for the 

 eminent botanist. Dr. George Engelmann.) 



I. E. pinnatifida, Torr. & Gray. Stems 1-2° high; heads |' broad, 

 and rays ^' long. — Central Kan. to La., and westward. 



41. PARTHENIUM, 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 cal- 

 lous 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 irapQevos, virgin.) 



1 P. integrifolium, L. Rough-pubescent perennial (1-3° high); 

 leaves oblong or ovate, crenate-toothed, or the lower (3 -6' long) cut-lobed be- 

 low the middle ; heads many in a very dense flat corymb. — Dry soil, Md. to 

 111., Minn., and southward. June - Aug. 



42. IV A, 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 f uunel-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 shrubliy coarse plants, with thickish leaves, tlie 

 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 ofJeax-es or leaf-like bracts ; fertile 

 flowers with evident coroUa. 



1. I. frutescens, L. Shrubbi/ at the base, nearly smooth (3-8° high); 

 leaves oval or lanceolate, coarsely and sharply toothed, rather fleshy, the ujiper 

 reduced to linear bracts, in the axils of which the heads are disposed, in leaf\^ 

 pauicled racemes ; fertile flowers and scales of the involucre 5. — Salt marshes, 

 coast of Mass. to Va. and southward. 



2. I. ciliata, Willd. Annual (2-6° high), rough and hairy ; leaves ovate, 

 pointed, coarsely toothed, downy beneath, on slender ciliate petioles; heads in 

 dense spikes, with conspicuous ovate-lanceolate rough-ciliate bracts ; scales of 

 the involucre and fertile flowers 3-5 — Moist ground, from 111. southward. 



