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

[+] Leaves alternate, entire. Disk-flowers purplish.

58. Baldwinia. Rays numerous, long, neutral. Involucre much imbricated. Receptacle deeply honey-combed.

59. Marshallia. Rays none. Involucre of narrow leafy equal scales. Receptacle chaffy.

[+][+] Leaves opposite, serrate. Disk-flowers yellow.

60. Galinsoga. Rays few, short, pistillate, whitish. Involucre of 4–5 thin ovate scales. Receptacle chaffy.

Tribe VI. HELENIOIDEÆ. Nearly as Tribe V., but receptacle not chaffy (somewhat so in n. 64). In our genera, the disk-flowers perfect and fertile; the pappus a row of several chaffy scales (bristly-dissected in n. 65); the involucre hardly at all imbricated (partly scarious in n. 61).

[*] Involucral scales distinct, not glandular-punctate.

61. Hymenopappus. Rays none. Receptacle flat. Involucre colored. Western.

62. Actinella. Rays fertile, 3-toothed. Receptacle elevated. Involucre appressed. Western.

63. Helenium. Rays fertile or sterile, 3–5-cleft. Receptacle elevated. Involucre small, reflexed. Leaves decurrent.