23. Townsendia. Low or stemless, with linear-spatulate leaves and large aster-like flowers.
[+][+][+] Pappus of numerous long and capillary bristles; receptacle flat.
24. Sericocarpus. Heads 12–20-flowered; rays 4 or 5. Involucre oblong or club-shaped, imbricated, cartilaginous. Achenes short, narrowed downward, silky.
25. Aster. Heads many-flowered, on leafy peduncles. Involucral scales unequal, loosely or closely imbricated. Achenes flattish; pappus simple (rarely double), copious.
26. Erigeron. Heads many-flowered, on naked peduncles. Involucre of narrow equal scales, little imbricated. Achenes flattened; pappus simple and rather scanty, or with some outer minute scales.
[*] 3. Rays none. Heads diœcious (all pistillate or all staminate).
27. Baccharis. Heads many-flowered. Pappus capillary. Smooth glutinous shrubs.
Tribe IV. INULOIDEÆ. Heads discoid (radiate only in Inula), the pistillate flowers mostly filiform and truncate. Anthers sagittate, the basal lobes attenuate into tails. Style-branches with unappendaged obtuse or truncate naked tips. Pappus capillary or none.
[*] 1. Receptacle naked. Involucre not scarious, imbricated. Not woolly.
28. Pluchea. Heads containing a few perfect but sterile flowers in the centre, and many pistillate fertile ones around them. Pappus capillary.