DICOTYLEDONOUS PLANTS 227 
I. TUBULIFLORZ. 
A.} 
Corollas some or all of them tubular. 
Rays white, pink, or purplish. 
Rays many; akenes flat; pappus wanting; low herbs. Bellis, I. 
Rays many; akenes cylindrical or winged, grooved; pappus 
wanting ; tall herbs or shrubby. Chrysanthemum, VIII. 
Rays many; akenes flat; pappus of an outer row of minute 
scales and an inner row of delicate bristles. Erigeron, II. 
Rays many; akenes cylindrical or ribbed; pappus wanting ; | 
strong-scented branching herbs. Anthemis, VI. 
Rays few. Achillea, VII. 
Rays yellow. 
Disk purplish-brown. Rudbeckia, IV. 
Disk yellow. 
Involucre of 2 rows of bracts, the outer rather leaf-like. 
Coreopsis, III. 
Involucre of reflexed scales; pappus of 5-8 scales. 
Helenium, V. 
Involucre of erect scales ; pappus of abundant soft hairs. 
Senecio, IX. 
Rays none, but the marginal flowers sterile and their tubular 
corollas partly flattened like rays (Fig. 24). Centaurea, X. 
Rays none and marginal flowers like the others; scales of the 
involucre overlapping in many rows, prickly-pointed. 
Cirsium, XI. 
B. 
Corollas all strap-shaped. 
Corollas blue (rarely pinkish); akenes not beaked. 
Cichorium, XIII. 
Corollas blue; akenes beaked. Lactuca, XVIII. 
1 The characters in this key are not necessarily true of all species in the genera 
referred to, but only of those described below. 
