BOTANY OF LA SALLE COUNTY. 97 



der rays W. disc Y. 12 to 18 in. Roadsides. 



ACHILLEA. P. Yarrow. Heads small in carymbs. 



W. or R. 



A. millefolium. Stems grooved. 2 to 3ft.; leaves 

 mostly radical, cut into hair-like divisions. 



TANACETUM. P. Tansy. Very bitter and strong- 

 scented. 



T. vulg-are. Smooth, 1 to 3 ft., leaves 1 to 3 pin- 

 nately divided, serrate; head almost rayless, Y. 



T. vulg-are. var. Crispum. Leaves crisped. 

 Escaped from yards. 



ARTEMISIA. P. Bitter and aromatic herbs. 



A. dracunculoides. Slightly hoary; leaves linear, 

 entire or 3 cleft; heads small, many; 2 to 5 ft. 



A. ludoviciana. White-woolly; upper leaves en- 

 tire, lower cut and lobed; heads sessile. Vari- 

 able, 1 to 5 ft. 



A. biennis. Leaves more or less divided; lobes 

 linear, acute; heads in spikes forming' a leafy 

 panicle. 1 to 3 ft. 



A. absin thum. A bitter, silky-hoary, shrubby 

 plant of the g-arden. 



SENECIO. P. Groundsel. Leaves alternate; heads 



solitary. 

 S. aureus. Golden Rag-wort. Squaw-weed. 



Leaves cordate, crenate; lyrate or lanceolate 



. lobe.d; small; heads small on long- peduncles, 



forming- a corymb; X i n - broad, Y. 8 to 20. in. 



CACALIA. P. Smooth; stems tall, 2 to 5 ft., 



leaves alternate. 

 C. atriplicifolius. Stems round; leaves rhomboid, 



angled; heads W., rayless. 

 C. tuberosa. Stem angled and grooved, 2 to 6 ft. 



