Thymophylla tenuifolia (Cass.) Rydb.

Thymophylla tenuifolia (Cass.) Rydberg
Hymenatherum tenuifolium Cass. Diet. Sei. Nat. 22: 314. 1821. Dyssodia tenuifolia Loesener, Bull. Herb. Boiss. II. 6: 866. 1906.
A glabrous annual; stem diffusely branched, 1-2 dm. high; leaves mostly alternate, 2-3 cm. long, pinnatifid into 7-11 filiform divisions; peduncles 2-4 cm. long, minutely bracteolate; involucre turbinate, 5 mm. high, 6-7 mm. broad, without calyculum; bracts about 15, oblanceolate, with broad, abruptly short-acuminate tips and 3-5 more or less raised glands; ligules oval, 5 mm. long, 3 mm. wide; disk-corollas 3 mm. long; tube shorter than the elongatefunnelform throat; lobes ovate ; achenes slender, angled, 2 mm. long, hispidulous; pappus usually double; principal squamellae 10, about 2.5 mm. long; body oblong or ovate, 3-toothed at the apex, the middle tooth long-awned, the lateral ones awn-pointed; accessory outer squamellae 1-3, minute, subulate.
Type locality: Chile, but the specimen of uncertain source. Distribution: San Luis Potosi to Mexico (State).

Thymophylla diffusa (A. Gray) Rydberg
Hymenathenim diffusum A. Gray, PI. Wright. 1: 116. 1852. Dyssodia diffusa B. L. Robinson. Proc. Am. Acad. 49: 507. 1913.
A glabrous annual; stem diffuse or decumbent, 1-2 dm. long; leaves alternate or opposite,
1-3 cm. long, pinnatifid, with filiform divisions; peduncles 1-3 cm. long, minutely bracteolate;
involucre turbinate, 5 mm. high, 7 mm. broad, without accessory bracts; ligules oval, 4 mm.
long; disk-corollas 3 mm. long; tube shorter than the elongate-funnelform throat; lobes ovate;
achenes slender, 3 mm. long, hispidulous; squamellae 10, narrowly oblong, 3-toothed, the middle
tooth long-awned, the lateral ones awn-pointed, and erose-laciniate on the margins.
Type locality: Mexico. Distribution: Chihuahua.

Thymophylla tenuifolia là một loài thực vật có hoa trong họ Cúc. Loài này được (Cass.) Rydb. miêu tả khoa học đầu tiên năm 1915.