CL. XIX.] SYNGETtfESTA. 305 



** Corollas of the marginal florets strap-shaped. 



36. BEXLIS. Receptacle naked, conical. Seed-down none. Calyx 



hemispherical ; scales equal. Seed inversely egg-shaped. 



39. MATRICA'RIA. Receptacle naked, nearly cylindrical. Seed- 



down none. Calyx hemispherical or nearly plane, imbricated ; 

 the scales membranous on the edges. 



37. CHRYSA'NTHEMUM. Receptacle naked, a little convex. 



Seed-down none. Calyx hemispherical, imbricated ; the scales 

 with a dilated membranous border. 



38. PYRETHRUM. Receptacle naked. Seed crowned with a mem- 



branous border. Calyx hemispherical, imbricated ; the scales 

 rather acute, membranous at the edges. 



35. DORO'NICUM. Receptacle naked. Seed-down simple, want- 

 ing on the seeds of the rays. Calyx a double row of equal 

 scales, longer than the disk. 



33, I'NTJLA. Receptacle naked. Seed-down simple. Calyx hemi- 



spherical, imbricated. Marginal florets very numerous, linear. 

 Anthers with two bristles at the base. 



27. ERI'GERON. Receptacle naked. Seed-down simple. Calyx 



imbricated. Marginal florets numerous, linear, very narrow. 



AntJiers without bristles. 

 32, SOLIDA'GO. Receptacle naked, pitted. Seed-down simple. 



Calyx imbricated, its scales close. Marginal florets abomt five. 

 31. AfSKEU-pReceptacle naked. Seed- down simple. Calyx imbricated, 



the lower scales spreading. Marginal florets more than ten. 

 SO. SENE'CIO. Receptacle naked. Seed-down simple. Calyx 



double ; the inner cylindrical, of equal scales ; the outer of 



several minute ones ; all the scales withered-looking at the tip. 



28. TUSSILA'GO. Receptacle naked. Seed-down simple. Calyx 



simple, swelled at the base ; scales numerous, equal, some- 

 what membranous. Corolla rayed. 



29. PETASI'TES. Receptacle naked. Seed-down simple. Calyx 



egg-shaped, imbricated with two rows of lanceolate scales. 

 Florets tubular. 



34. CINERA'RIA. Receptacle naked. Seed-down simple. Calyx 



simple, cylindrical; scales numerous, equal. Seed four- 

 cornered. 



40. A'NTHEMIS. Receptacle convex, chaffy. Seeds crowned with 



a membranous border. Calyx hemispherical ; its scales nearly 

 equal, their margins membranous. 



41. ACHILLE'A. Receptacle flat, chaffy. Seed-down none. Calyx 



egg-shaped, imbricated; the scales unequal. Marginal florets 

 few, roundish. 



(Bidens cernua.) 



Order III. POLYGAMIA FRUSTRANEA. 



Florets of the disk perfect and fertile ; those of the circum- 

 ference destitute of both stamens and pistil. 



42. CENTAURE'A. Rimeptacle bristly. 'Seed-down simple or fea- 



thery. Calyx imbricated. Marginal florets funnel-shaped, 

 dilated, irregular. 



