COMPOSITE FAMILY 241 
Rays yellow. 
Disk purplish-brown. Rudbeckia, IV 
Disk gray. Lepachys, V 
Disk yellow. 
Involucre of 2 rows of bracts, the outer rather leaf-like. 
Coreopsis, VI 
Involucre of reflexed scales ; pappus of 5-8 scales. 
Helenium, VII 
Involucre of erect scales; pappus of abundant soft hairs. 
Senecio, XI 
Rays none, but the marginal flowers sterile and their tubular 
corollas partly flattened like rays. Centaurea, XIII 
Rays none, and marginal flowers like the others; scales of the in- 
volucre not-prickly. Antennaria, III 
Rays none and marginal flowers like the others; scales of the in- 
volucre overlapping in many rows, prickly-pointed. 
Cirsium, XII 
II. LIGULIFLORA 
Corollas all strap-shaped. 
Corollas blue (rarely pinkish); 
akenes not beaked. 
Cichorium, XIV 
Corollas blue; akenes beaked. 
Lactuca, XTX 
Corollas yellow. 
(a) Akenes truncate ; pappus double, 
of chaff and bristles. 
Krigia, XV 
(b) Akenes columnar; pappus of 
tawny, rough bristles ; stem A 
scape-like. 
Hieracium, XXII i toca an aati a 
. 1, smooth hair of dandelion; B, 
(c) Akenes spindle-shaped, not plumose hair of fall dandelion ; 
beaked; pappus of plumed C’, rough or barbed hair of 
2 hawkweed. (7 times natural 
bristles. | Leontodon, XVI size) : 
Fig. 31. Types of pappus hairs 
