Low shrubs, with equably leafy branches, hard wood, linear leaves, and discoid heads of yellow perfect flowers. Heads narrow, 5-7-flowered. Involucre oblong to narrowly campanulate, its bracts more or less keeled, thin, or papery, impricated in several series, often so as to form 5 vertical rows. Corolla 5-toothed. Anthers obtuse at the base. Style-branches exserted, their appendages subulate to filiform. Achenes narrow, mostly pubescent. Pappus of copious capillary roughened bristles. [Greek, golden-bush.]

About 30 species, natives of western North America. Type species: Chrysothamnus pumilus Nutt. Heads about 6" high; involucral bracts obtuse or mucronulate.

1. C. graveolens.

Heads 7"-10" high; involucral bracts subulate-tipped.

2. C. Howardi.

16 Chrysothamnus Nutt Trans Am Phil Soc II 7 323 1 875

1. Chrysothamnus Graveolens (Nutt.) Greene. Fetid Rayless Golden-Rod

Fig. 4204

Chrysocoma graveolens Nutt. Gen. 2: 136.

1818. Bigelovia graveolens A. Gray, Proc. Am. Acad.

8: 644. 1873. Chrysothamnus graveolens Greene, Erythea 3:

108. 1895.

Sparingly tomentose above, or glabrate, much branched, very leafy, 1°-4 1/2° high, odorous. Leaves linear, 1'-3' long, 1"-2" wide; heads 5"-6" high, very numerous and crowded in terminal compound corymbose cymes; rays none; involucre narrowly campanulate, acute at the base, its bracts oblong or linear-oblong, acute or acutish, imbricated in about 4 series; achenes linear; pappus-bristles soft, copious.

In sterile, especially alkaline soil, Montana to western Nebraska, Utah and New Mexico. Included in our first edition in the C. nauseosa (Pursh) Britton, a densely tomentose far western species. Rabbit-brush. Aug.-Oct.

2. Chrysothamnus Howardi (Parry) Greene. Howard's Rayless Golden-Rod

Fig. 4205

Linosyris Howardi Parry; A. Gray, Proc. Am. Acad. 6: 541. 1865.

Bigelovia Howardi A. Gray, Proc. Am. Acad. 8: 641. 1873.

Chrysothamnus Howardi Greene, Erythea 3: 113. 1895.

Similar to the preceding species, white-tomentose when young, glabrous or nearly so when old, tufted, much branched, 6-10' high. Leaves narrowly linear, entire, 1'-2' long, about 1" wide; heads 7"-10" long, narrow, 5-flowered, more or less glomerate, usually surpassed by the upper leaves; rays none; involucre slightly arachnoid-pubescent, its bracts lanceolate, thin, acuminate or subulate-tipped; achenes nearly linear, pubescent.

In dry soil, western Nebraska to Wyoming, Colorado, Utah and New Mexico. July-Sept.

2 Chrysothamnus Howardi Parry Greene Howard s Rayl 876