260 CARDUACEAE 



Heads few, clustered. . , „ , j ■ ,. 



Heads more or less peduncled; basal leaves obovate-cuneate, with 3-5 round lopes 



at the apex. 2. S. argenlea. 



Heads sessile in a capitate cluster; basal leaves once or twice ternateljr diviaea 

 into linear or oblong divisions. 3. S. capitata. 



Heads solitary, basal leaves simple, linear, or ternately cleft at the apex into linear 

 divisions. 4. S. simplex. 



122. PICROTHAMNUS Nutt. l. P- desertorum. 



123. ARTEMISIA L. Wormwood, Mugwort, Cudweed, Sage Brush. 

 Disk-flowers sterile, their styles undivided or with short erect branches ; receptacle naked. 



Annual or perennial herbs; style of the disk-flowers undivided, ending in a cup- 

 shaped penicillate appendix. I. Dracunculoides. 

 Low shrubs or undershrubs ; style of the disk-flowers usually more or less 2-eleft, each 

 branch erect with truncate penicillate or erose apex. II. Filifoliae. 

 Disk-flowers fertile, their styles 2-cleft; branches more or less recurved. 

 Marginal pistillate flowers present. 

 Receptacle hairy. 



Heads numerous, usually paniculate: plant more or less shrubby at the base. 



III. FniGIDAE. 

 Heads few, 1-12, racemose; plant low, herbaceous, from a rootstock, 1-3 dm. 

 high IV. Lanatae. 



Receptacle naked. 



Amiual or biennial herbs with bipinnatifld leaves. V. Annuae. 



Perennials. 



Leaves silvery or silky or glabrate, but not tomentose beneath. 



Plants low, herbaceous perennial, with rootstocks; heads many-flowered, 

 nodding in a simple racemose inflorescence; leaves divided into linear 

 or oblong divisions. VI. Norvegicae. 



Plants more or less shrubby at the base; heads paniculate. 



Leaves pinnately dissected into narrow divisions (glabrate forms of 



A. Abrotanum, A. graveolens and A. tenuis). 

 Leaves cuneate, 3-toothed at the apex or the upper entire. 



XIII. Bigelovianae. 

 Leaves more or less tomentose beneath. 



Leaves not dissected into narrowly linear more or less divergent divi- 

 sions; these, if narrow, very few, directed forward and entire. 

 Leaves greener and glabrate above, at least in age. 



Heads 60-100-flowered; leaves twice pinnatifld with obtuse 

 divisions, the lower long-petioled. 



VII. Fr.\nsebioides. 

 Heads 5-50-flowered ; leaves simple or once pinnatifld, or if bi- 

 pinnatifld, with acute lobes and sessile or short-petioled. 

 Leaves entire or with a few lobes, if dissected to near the 

 midrib, the lobes rather broad [except in A. mexicana]. 



VIII. Vulgares. 

 Leaves deeply dissected to near the midrib; divisions linear 

 or oblong, usually more or less cleft. 



X. DiSCOLORES. 



Leaves white-tomentose on both sides. IX. Gnaphaloides. 



Leaves once or twice dissected into linear or filiform, more or less spread- 

 ing divisions. 

 Leaf-segments broadly linear or linear-lanceolate, usually again 



lobed or toothed. X. Discolores. 



Leaf-segments narrowly linear or filiform, mostly revolute. 



Leaves once pinnatifld; plant herbaceous; style of the ray-flow- 

 ers long-exserted. XI. Wrightianae. 

 Leaves twice pinnatifld; plant suftruticose; style of the ray- 

 flowers short-exserted. XII. PONTICAE. 

 Marginal pistillate flowers wanting; receptacle naked. 



Shrubs 1-50 dm. high; leaves canescent, not with raised midribs. 



Heads in terminal panicles; leaves entire, 3-5-toothed to 3-5-divided at the 



apex. XIV. Tridentatae. 



Heads axillary ; leaves pinnatifld into linear divisions. XV. RlGrD-^B. 

 Dwarf undershrubs, scarcely more than 1 dm. high ; leaves pinnatifld into Unear- 

 spatulate divisions, green, with the ribs raised beneath. 



XVI. Pygmaeae. 



I. Dracunculoides. 



Leaves all entire or the lower 3-fld. 



Leaves densely pubescent when young. 1. A. glauca. 



Leaves glabrous. 



Involucre 3-4 mm. broad; lower stem-leaves 3-12 mm. wide; heads 30-100-flow- 

 ered; outermost involucral bracts almost as long as the inner. 



2. A. aromatica. 

 Involucre 2-3 mm. broad; leaves 1-3 mm. wide; heads 20— 40-flowered ; outer 

 bracts much shorter than the inner. 3. A. dracunculoides. 



Leaves, at least the lower, pinnatifld or bipinnatifld. 



Heads very small, 2-3 mm. broad, numerous in large leafy panicles; plants mostly 

 tall, 3-10 dm. high. 



