Flora of the Palousc Region 197 



ally all fertile: involucre hemispherical or flatter, the scales more 

 or less scarious, short-appressed, imbricated in several rows: recep- 

 tacle flat or convex, naked: pappus none (in ours): disk- 

 corollas often obcompressed or 2-winged below, 4-5-toothed: 

 akenes short, nearly terete, several-ribbed or angled, truncate at 

 apex. 



C. leucanthemum L- Perennial, erect, 30-60 cm. high, glabrous or 



nearly so, usually simple: basal leaves oblong or spatulate, incisely pinnati- 

 fid or toothed: cauline smaller, sessile and partly clasping, linear: heads 3-5 

 cm. broad, on long naked peduncles: involucral-bracts oblong-lanceolate, 

 obtuse, rusty at tip: rays 20-30, white: akenes manj'-ribbed: pappus none. 

 Sparingly introduced. 



332. MATRICARIA. 



Herbs: very similar to Chrysanthemum but ray-flowers none 

 (in ours): involucre hemispherical or flatter, of numerous more or 

 less scarious appressed scales, in few rows: receptacle high-conical 

 or ovate: pappus none or a minute crown. 



M. discoidea DC. Annual, 5-15 cm. high, simple or branched, sparsely 

 pubescent or glabrous: leaves oblong, 1-3 cm. long, 1-2-pinnately dissected 

 into small linear acute segments: heads 5-9 mm. high, terminating short 

 stout peduncles: involucre saucer-shaped, the scales oblong, obtuse, green, 

 with scarious margins: ray-flowers none: disk-flowers yellowish-green: recep- 

 tacle conical: akenes oblong: pappus represented by a low sometimes 

 1-2-toothed crown. Dry ground, very common. 



333. ARTEMISIA. 



Herbs or undershrubs, bitter and odorous: leaves alternate, usu- 

 ally dissected: heads numerous, small, usually nodding, in 

 racemes or panicles, several to many-flowered, discoid: flowers 

 yellow or yellowish, all tubular, the outermost series pistillate, or 

 all alike, the more numerous perfect flowers either fertile or ster- 

 ile: involucral-scales dry, imbricated in a few rows, appressed: 

 receptacle flattish to hemispherical, naked, sometimes hairy: pap- 

 pus none: corollas of pistillate flowers slender and small, 2-3- 

 toothed, of the perfect flowers enlarged above, 5-toothed: akenes 

 obovoid or oblong, almost always glabrous. 



Green and glabrous. 



Perennial: leaves linear, mostly entire. A. DRANUNCUXOIDES. 



Biennial: leaves 1-2-pinnately parted. A. BIENNIS. 



Canescent or tomentose. 



Leaves narrowly 3-5-parted. A. rigida. 



Leaves and segments broader. 



Involucre white-tomeutose. A. i.idoviciaxa. 



Involucre glabrous or nearly so. A. INCOMPTA, 



A. draminculoides Pursh. Perennial, herbaceous, very odorous, usually 

 tufted, the slender stems 1-1.5 m. high, glabrous throughout: leaves linear, 



