[Hymenatherum Cass. Bull. Soc. Philom. 1817: 12. 1817.]

Annual or perennial herbs, some species low undershrubs, with gland-dotted foliage and involucre, alternate or opposite leaves, and small heads of both tubular and radiate, mostly yellow flowers. Involucre campanulate, its principal bracts united into a cup, sometimes with smaller outer ones. Receptacle naked, or fimbrillate, not chaffy. Ray-flowers pistillate, fertile. Disk-flowers perfect, fertile. Style-branches truncate or blunt. Achenes striate. Pappus of several or numerous scales or bristles. [Greek, thyme-leaf, not applicable to the following species.]

About 15 species, natives of America. Besides the following, some 4 others occur in the western parts of the United States. Type species: Thymophylla setifolia Lag.

87 Thymophylla Lag Gen Et Sp Nov 25 1816 1221

1. Thymophylla Aurea (A. Gray) Greene. Thyme-Leaf

Fig. 4550

Lowellia aurea A. Gray, Mem. Am. Acad. (II) 4: 91.

1849. Hymena herum aureum A. Gray, Proc. Am. Acad. 19:

42. 1883. T. aurea Greene; Britt. & Brown, 111. Fl. 3: 453. 1898.

Annual, glabrous, 4'-12' high, much branched; the leaves and involucre with large oval oil-glands. Leaves alternate, or the lower opposite, sessile or nearly so, very deeply parted into 5-9 linear-filiform, mostly entire, blunt segments; heads numerous, corymbose, 6"-10" broad, terminating the branches; involucre about 3" high, its bracts acute; rays about 12, 2 1/2"-3" long; pappus of 6-8 erose truncate scales, somewhat longer than the thickness of the achene.

Kansas and Colorado to Texas and New Mexico. June-Sept.