246 SYSTEMATIC BOTANY. 



4. S. ARGUTA (Sharp-toothed Golden-rod}. Smooth ; stem erect, thick, 

 furrowed ; leaves sharply serrate, with diverging teeth, acuminate, tapering 

 at base ; lower and radical ones oval-lanceolate or lanceolate, attenuate to 

 marginal and ciliate petioles ; cauline ones lanceolate, or oblong, the highest 

 entire. 



9. Inula. Heads many-flowered, involucre imbricated. Rays 

 numerous in one row. Disk-flowers perfect. Receptacle naked. Pap- 

 pus capillary, y. 



HELENIUM. Stem stout; leaves ovate, serrate; heads very large, 

 solitary, terminating the branches ; rays linear, light yellow, 2-3-toothed at 

 apex; involucre-scales ovate, foliaceous. Common by roadsides, 4-6 feet 

 high. July-August. 



10. Helianthus. Heads many-flowered. Rays neutral. Disk- 

 flowers perfect. Involucre-scales imbricated in several rows. Chaff 

 persistent with the 4-sided, laterally compressed achenia. Pappus of 

 2 deciduous, chaffy awns. y 



1. H. ANNUUS (Sunflower). Leaves cordate, petiolate, 3- veined, the low- 

 est opposite the others, alternate ; heads very large, on nodding peduncles ; 

 rays numerous, broad, bright yellow. In cultivation, 8-10 feet high. July- 

 September. 



2. H. DECAPETALUS (Ten-rayed Sunflower). Stem tall, branching, 

 rough above, smooth below ; leaves opposite, ovate, acuminate, coarsely ser- 

 rate, 3-veined, of the same color on both sides, abrupt at base, with winged 

 petioles ; heads rather large, with about 10 pale-yellow rays ; involucre-scales 

 linear-lanceolate, spreading. Along river-banks, 2-5 feet high. August- 

 September. 



3. H. DIVARICATUS (Slender Sunflower}. Stem smooth, simple, or 

 sparingly branched ; leaves opposite, ovate-lanceolate, 3-veined, sessile, ser- 

 rate, rough above ; heads small, few, somewhat corymbose ; involucre-scales 

 lanceolate, acuminate. In dry grounds, 2-5 feet high. August-September. 



11. Achillea. Heads many-flowered. Rays 5-10, pistillate. In- 

 volucre with imbricate, unequal scales. Receptacle flat, chaffy. Pap- 

 pus none. y. 



A. MILLEFOLIUM ( Yarrow}. Stem erect, furrowed, branching above ; 

 leaves alternate, bi-pinnately divided, segments linear, toothed or lobed ; 

 heads small, numerous., in dense, flat, terminal corymbs ; rays about 5, short, 

 white (sometimes rose-color) ; involucre furrowed, oblong. In fields, i foot 

 high. June-August. 



12. Leucanthemum. Heads many-flowered. Rays numerous, 

 pistillate. Involucre depressed, flattish ; scales imbricated, with sca- 

 rious margins. Receptacle naked, flat. Achenia striate. Pappus 

 none. y. 



L. VULGARE (Ox-eye Daisy). Stem erect, simple, or sparingly branched, 

 furrowed. Leaves few and rather small, cut pinnatifid, incised at base ; 



