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

74. Arnica. Heads showy. Pappus rather rigid, scabrous.

[+][+] Leaves alternate. Pappus soft-capillary, copious.

75. Senecio. Heads usually radiate. Corollas yellow, 5-toothed.

76. Cacalia. Heads discoid. Corollas white or cream-colored, 5-cleft.

77. Erechtites. Heads discoid. Flowers whitish, the outer pistillate with filiform corollas.

Tribe IX. CYNAROIDEÆ. Flowers all tubular and perfect (the outer ray-like and neutral in n. 82). Involucre much imbricated. Anthers caudate, long-appendaged at tip. Style-branches short or united, obtuse, unappendaged, smooth, with often a pubescent ring below. Pappus mostly bristly.—Leaves alternate.

[*] Achenes attached by the base. Flowers all alike.

[+] Leaves not prickly. Style-branches partly distinct. Filaments glabrous.

78. Arctium. Involucral scales hooked at the tip. Pappus of short rough bristles.

[+][+] Leaves prickly. Style-branches coherent, usually a pubescent ring below.