CAEDUACEAE. 309 



rather narrow, but mostly broadeued upward. Kay-corollas with ligules longer 

 than wide. Filaments adnate to the corolla-tube. Achenes terete or angled. 

 Pappus a scaly cup, or wanting. — Sum. — Daisy. 



Ray conspicuous ; ligules linear : heads few or solitary. 1. C. Leucanthemum. 



Ray inconspicuous ; ligules oval or obovate : heads numerous. 2. C. Parthenium. 



1. C. Leucanthemum L. Plants 2-9 dm. tall, glabrous or nearly so: leaf- 

 blades spatulate to linear, 2-10 cm. long, serrate or pinnatifid: inner bracts of 

 the involucre 5.5-6.5 mm. long, obtuse: ray-flowers numerous; ligules white or 

 pink, 1-2.5 cm. long: disk yellow: pappus obsolete. — Common, in fields and 

 waste places. Nat. of Eu. — White-daisy. Ox-eye daisy. 



2. 0. Parthenium (L.) Pers. Plants 2-7 dm. tall: leaf -blades broad, those of 

 the lower ones at least, twice pinnately parted, the divisions incised: inner 

 bracts of the involucre 2.5-3 mm. long, acute: ligules white, 3-5 mm. long: 

 disk cream-colored : pappus a toothed crown. — M. Frequent, on roadsides 

 and about gardens. Nat. of Eu. — Feverfew. 



42. TANACETUM L. Perennial or sometimes annual herbs. Leaves 

 alternate: blades pinnately dissected or divided. Heads corymbose. Involucre 

 hemispheric or saucer-shaped: inner bracts longer than the outer. Filaments 

 partly adnate to the corolla-tube. Achenes angled or ribbed. Pappus a 

 crown-like border. 



1. T. vulgare L. Plants 3-10' dm. tall, acrid-aromatic: leaf -blades 5-20 cm. 

 long, with the ultimate segments sharply toothed : involucres 6-8 mm. wide, 

 the inner bracts 4-5 mm. long : corollas yellow : achenes about 2 mm. long. — 

 Common, on roadsides and about gardens. Nat. of Eu. — Sum. — Tansy. 



43. AKNICA L. Perennial herbs. Leaves typically opposite: blades 

 entire or toothed. Heads solitary or several. Involucre mostly turbinate or 

 campanulate, or broader in age: bracts nearly equal, narrow. Kay-flowera 

 with yellow ligules. Corollas of the disk-flowers tubular, the lobes very short. 

 Achenes ribbed. Pappus a single series of slender bristles. 



1. A. acaulis (Walt.) B.S.P. Plants 2-10 dm. tall, hirsute: leaves mainly 

 basal and spreading on the ground; blades oblong to oval or ovate, 5-12 cm. 

 long, shallowly toothed or nearly entire: bracts of the involucre 9.5-11 mm. 

 long, acute: ligules 1.5-2.5 cm. long: achenes 4 mm. long. — S. Bare, in 

 low grounds near New Texas. — Schists. — Sum. 



44. EBECHTITES Eaf. Annual herbs. Leaves alternate: blades toothed 

 or pinnatifid. Heads corymbose or paniculate. Involucres narrow and some- 

 what swollen at the base: bracts narrow, flat. Disk-corollas with triangular- 

 lanceolate or deltoid lobes shorter than the narrow throat. Filaments longer 

 than the anthers. Achenes ribbed. Pappus of many white bristles. 



1. E. hieracifolia (L.) Eaf. Plants 2-20 dm. tall, watery: leaf -blades spatu- 

 late-oblong to lanceolate, 5-20 cm. long, coarsely toothed, incised, or pin- 

 natifid: involucres 12-15 mm. long; bracts narrowly linear: corollas 8-9 mm. 

 long: achenes about 1.5 mm. long. — Common in clearings and fields. — Sum. 



FiREWEED. 



45. MESADENIA Eaf. Perennial herbs. Leaves alternate: blades un- 

 dulate, toothed or somewhat lobed. Heads corymbose. Involucres cylindric to 

 cylindric-ovoid: bracts sometimes winged or keeled. Disk-corollas with linear 

 or linear-lanceolate lobes longer than the campanulate throat. Filaments 

 filiform. Achenes ribbed, glabrous. — Sum. — Indian-plantain. 



