Genus S5.] 



THISTLE FAMILY. 



457 



85. CHRYSANTHEMUM L. Sp. PI. 888. 1753. 



Perennial or annual, mostly erect and branching herbs, with alternate dentate incised 

 or dissected leaves, and large, usually long-peduncled heads of both tubular and radiate flow- 

 ers, or rays rarely wanting. Involucre hemispheric or depressed, its bracts appressed, im- 

 bricated in several series, the outer shorter. Receptacle flat, convex or hemispheric, naked. 

 Ray-flowers pistillate, fertile, the rays white, yellow or rose-colored, entire or toothed. Disk- 

 flowers perfect, fertile, their corollas with terete or 2-winged tubes and 4-5-cleft limbs. An- 

 thers obtuse and entire at the base. Style-branches of the disk-flowers truncate, penicillate. 

 Achenes angled or terete, 5-10-ribbed, those of the ray-flowers commonly 3-angled. Pappus 

 none, or a scaly cup. [Greek, golden-flower.] 



About ioq species, of wide geographic distribution in the northern hemisphere. Besides the 

 following, 2 others occur in northwestern arctic America. Our species have white ray-flowers. 

 Heads large, few or solitary at the ends of the stem or branches. 



Stem-leaves linear-spatulate, pinnately incised; weed. 1. 



Stem-leaves cuneate-spatulate, toothed or lobed above; arctic. 2. 



Heads numerous, small, corymbose; plants escaped from gardens. 



Leaves pinnatifid, the segments incised. 3. 



Leaves oblong, serrate. 4- 



C. Leucanthemum. 

 C. arcticum. 



C. Parthenium. 



C. Balsamita. 



i. Chrysanthemum Leucanthemum L. White-weed. White or Ox-eye 

 Daisy. (Fig. 3988.) 



C. Leucanthemum L Sp. PI. 888. 1753. 

 Leucanthemum vulgare Lam. Fl. Fr. 2: 137. 



1778. 



Perennial; stem glabrous, or sparingly pu- 

 berulent, simple or little branched, i-3 

 high, often tufted, the branches nearly erect. 

 Basal leaves obovate, oblong, or spatulate, 

 coarsely dentate or incised, narrowed into 

 long slender petioles; stem-leaves mostly 

 sessile and partly clasping, l / ~3 / long, linear- 

 spatulate or linear, pinnately incised or 

 toothed, the uppermost very small and nearly 

 entire; heads few or solitary, i / -2 / broad, on 

 long naked peduncles; rays 20-30, white, 

 spreading, slightly 2-3-toothed; bracts of the 

 involucre oblong-lanceolate, obtuse, mostly 

 glabrous, with scarious margins and a brown 

 line within the margins; pappus none. 



In pastures, meadows and waste places, com- 

 mon throughout our area as a weed, but less 

 abundant in the south and west. Naturalized 

 from Europe. Native also of Asia. Other Eng- 

 lish names are Dog-, Bull-, Butter-, Big-, Mid- 

 summer-, Moon-, Horse-, Poorland- or Maudlin-Daisy, Dutch Morgan, Moon-flower, Moon- 

 Great White Ox-eye, Poverty- weed, White Man's 

 Herb-Margaret. Rays rarely short and tubular, 

 bright yellow. May-Nov. 



penny, 

 Weed, 



Disk 



Chrysanthemum arcticum L. 

 Daisy. (Fig. 3989. ) 



Arctic 



Chrysanthemum arcticum L. Sp. PI. 889. 1753- 

 Leucanthemum arcticum DC. Prodr. 6: 45. 1837. 



Similar to the preceding species, but somewhat 

 fleshy, lower, seldom over \ l / z high. Leaves cune- 

 ate-spatulate, i8 // -3 / long, crenate or cleft at the 

 apex, narrowed into a long tapering entire base, or the 

 lower into slender petioles, slightly clasping at the 

 base, the uppermost few, small, linear and nearly en- 

 tire; heads solitary or few, long-peduncled, i / -2 / 

 broad; rays 20-30, white; bracts of the involucre ob- 

 long, obtuse, brown, or with broad brown scarious 

 margins, usually pubescent; pappus none. 



Coast of Hudson Bay to Alaska. Also in arctic 

 Europe and Asia. Summer. 



