COMPOSITES 439 



17. BfiLLIS. GARDEN DAISY. 



Low tufte'd herbs with many-flowered heads, solitary on scapes: leaves 

 spatulate, petioled: flowers both radiate and tubular, mostly double, with 

 margins of the rays various, quilled, and otherwise modified in the cul- 

 tivated forms: ray flowers white or pink, pistillate; disk flowers yellow, 

 perfect with tubular corolla, limb 4-5-toothed: achenes flattened, wingless, 

 nerved near margins. 



B. perennis, Linn. English daisy. European garden daisy. Fig. 200. 

 Flower-head on a scape 3-4 inches high, from radical leaves, %-l in. in 

 diameter, with numerous linear rays, white, pink, bluish. Europe. Perennial. 

 Cultivated in gardens or on lawns. April to November. 



18. HELIANTHUS. SUNFLOWER. Figs. 3, 4. 



Stout, often coarse perennials or annuals, with simple alternate or 

 opposite leaves and large yellow-rayed heads: ray florets neutral; scales of 

 involucre overlapping, more or less leafy ; torus flat or convex, with a bract 

 embracing each floret: achene 4-angled: pappus of 2 scales (sometimes 2 

 other smaller ones), which fall as soon as the fruit is ripe. 



a. Disk brown. 



H. annuus, Linn. Common sunflower. Tall, rough, stout annual, with 

 mostly alternate stalked ovate-toothed large leaves: scales of involucre ovate- 

 acuminate, ciliate. Minnesota to Texas and West, but everywhere in gardens. 



H. scaberrimus, Ell. Prairie sunflower. Stout perennial (2-6 ft.), rough: 

 leaves oblong-lanceolate, entire or serrate, rough and grayish, thick and 

 rigid: heads nearly solitary, with 20-25 rays. Prairies, Michigan, west. 



aa. Disk yellow (anthers sometimes dark). 



H. giganteus, Linn. Tall, to 10 ft., rough or hairy: leaves mostly 

 alternate, lanceolate-pointed, finely serrate or quite entire, nearly sessile: 

 scales linear-lanceolate, hairy; rays pale yellow, 15-20. Low grounds. 



H. divaricatus, Linn. Figs. 3, 4, 23, 28. Small for the genus, 1-4 ft.: 

 leaves opposite, ovate-lanceolate, 3-nerved, sessile, serrate, rough and 

 thickish: rays 8-12, 1 in. long. Common in dry thickets. 



H. tuberSsus, Linn. Jerusalem artichoke. Bearing edible stem-tubers 

 below ground : 5-10 ft. : leaves ovate to oblong-ovate, toothed, long-petioled : 

 scales not exceeding the disk: rays 12-20, large. Pennsylvania west, and 

 cultivated. 



19. TANACfiTUM. TANSY. 



Tufted perennials, with finely divided leaves and strong odor: involucre 

 of overlapping dry scales; torus convex; heads small, nearly or quite rayless, 

 the flowers all seed-bearing: achenes angled or ribbed, bearing a short 

 crown-like pappus. 



T. vulgare, Linn. Common tansy from Europe, but run wild about old 

 houses: 2-4 ft.: leaves 1-3-pinnately cut: heads yellow, pappus-crown 

 5-lobed. 



