332 
CARDUACEAE. 
Bracts broad with a distinct keel or mid-vein, not at all 
foliaceous. 27. Eucephalus. 
Bracts usually narrow, when broad neither keeled nor with a 
prominent mid-vein. 28. Aster. 
Annuals or biennials, or if short-lived perennials, not with root¬ 
stocks ; bracts in many series, with herbaceous spreading or re¬ 
flexed tips; stigma-tips linear to filiform. 
29. Machaeranthera. 
Stigma-tips triangular or ovate, obtuse or rarely acutish; bracts not 
foliaceous. 
Involucres turbinate; bracts well imbricated in several rows. 
30. Leucelene. 
Involucres hemispherical or broader; bracts in 1-3 series. 
31. Erigeron. 
II. Marginal pistillate flowers not ligulate, reduced to a filiform or narrow 
short tube. 33. Eschenbachia. 
B. Heads unisexual, dioecious, discoid; pappus of the staminate flowers with 
clavate tips. 34. Baccharis. 
Tribe 4. GNAPHALIAE. 
Shrubs ; bracts coriaceous ; receptacle naked; pistillate flowers numerous; corolla 
reduced to a short slender tube; hermaphrodite flowers few and sterile; 
their pappus with clavate tips. 35. Berthelotia. 
Herbs, if at all shrubby only at the base ; bracts more or less scarious. 
Receptacle chaffy; stigmas of the hermaphrodite sterile flowers not truncate. 
36. Filago. 
Receptacle not chaffy; stigmas of the hermaphrodite flowers mostly truncate. 
Plants dioecious, or the pistillate heads with a few hermaphrodite flowers 
in the center. 
Pappus-bristles of the pistillate flowers falling off in a ring; those of the 
staminate flowers clavellate or apically barbellate, crisp; central 
hermaphrodite flowers none. 37. Antennaria. 
Pappus-bristles of the pistillate flowers falling off separately ; those of the 
staminate flowers scarcely clavellate; central hermaphrodite flowers pres¬ 
ent in the pistillate heads. 38. Anaphalis. 
Plants not dioecious; flowers fertile throughout the heads. 
39. Gnaphalium. 
Tribe 5. HELIANTHEAE. 
A. Bracts not enclosing the achenes of the rays; plants not glandular-viscid. 
I. Disk-flowers hermaphrodite but sterile. 
Marginal pistillate flowers with conspicuous rays; involucres of very dis¬ 
similar sets of bracts. 40. Melampodium. 
Marginal pistillate flowers reduced to a truncate or obliquely cleft tube; 
the ligule, if any, reduced to 2 or 3 small teeth. 41. Parthenice. 
II. Disk-flowers fertile. 
a. Ray-flowers fertile, with very short tube, persistent on the achenes and 
becoming papery in texture. 
Achenes of the disk compressed; leaves entire. 42. Crassina. 
Achenes obtusely 4-angled ; leaves toothed. 43. Heliopsis. 
b. Ray-flowers deciduous from the achenes or wanting. 
1. Pappus a crown or none, or of a few scales on the angles of the 
achenes and rarely minute ones between. 
a. Achenes of the disk-flowers not obcompressed (except in Ratibida) ; 
chaffs usually more or less concave and clasping. 
Receptacle conic, subulate or columnar. 
Achenes 4-angled. 44. Brauneria. 
Achenes quadrangular-compressed; apex of the achenes covered 
by the base of the corolla-tube. 45. Gymnolomia. 
Achenes nearly equally 4-angled; apex not covered by the base 
of the corolla. 46. Rudbeckia. 
Achenes flattened, broad-margined or winged. 
47. Ratibida. 
