The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

64. Gaillardia. Ray 3-toothed, or none. Receptacle usually beset with fine fimbrillate chaff. Outer involucral scales loose and leafy. Pappus-chaff tipped with the projecting midvein. Western.

[*][*] Dotted with oil-glands. Involucral scales united into a cup.

65. Dysodia. Pappus a row of chaffy scales dissected into many bristles.

Tribe VII. ANTHEMIDEÆ. Distinguished from the last two tribes by the more or less dry and scarious imbricated scales of the involucre. Heads radiate (ray mostly white) or discoid, the perfect flowers sometimes sterile and the pistillate rarely tubular. Achenes small; pappus a short crown or none.—Mostly strong-scented; leaves alternate.

[*] Receptacle chaffy, at least in part. Heads radiate, many-flowered.

66. Anthemis. Achenes terete, angled or ribbed. Heads hemispherical, rather large.

67. Achillea. Achenes obcompressed. Heads small, campanulate or obovate.

[*][*] Receptacle naked.

[+] Heads rather large, pedunculate, radiate or rarely rayless.

68. Matricaria. Receptacle conical. Rays pistillate or none. Pappus crown-like or none.