Thymophylla tenuiloba

(de Candolle) Small

Fl. S.E. U.S., 1295, 1341. 1903.

Basionym: Hymenatherum tenuilobum de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 462. 1836
Synonyms: Dyssodia tenuiloba (de Candolle) B. L. Robinson
Treatment appears in FNA Volume 21. Treatment on page 242. Mentioned on page 240.

Annuals (rarely persisting), green, to 30 cm, glabrous or sparsely hirtellous. Stems decumbent to erect. Leaves mostly alternate (sometimes opposite at 1–3 proximal nodes); blades usually lobed, 12–28 mm overall, lobes 7–15, linear to filiform, pliable (blades mostly not lobed in var. wrightii). Peduncles 30–80 mm, glabrous or hirtellous. Calyculi of 3–8 deltate to subulate bractlets, lengths less than 1/2 phyllaries. Involucres obconic, 5–7 mm. Phyllaries 12–22, margins of outer distinct less than 1/5 their lengths, abaxial faces glabrous or sparsely hirtellous. Ray florets 10–21; corollas yellow-orange, laminae 4–10 × 1.5–3 mm. Disc florets 50–100+; corollas yellow, 2.5–4.5 mm (peripheral ± zygomorphic in some plants). Cypselae 2–3.5 mm; pappi of erose and/or aristate scales 0.7–3.5 mm.


Varieties 4 (4 in the flora).

Selected References



1 Leaf blades seldom lobed (linear to spatulate, usually entire, rarely with 3–5 toothlike lobes) Thymophylla tenuiloba var. wrightii
1 Leaf blades lobed (lobes 7–15 linear) > 2
2 Pappi of 3–5-aristate scales Thymophylla tenuiloba var. tenuiloba
2 Pappi of truncate to lanceolate and/or 1-aristate scales > 3
3 Pappi of 5 erose scales alternating with 5unequal, 1-aristate scales Thymophylla tenuiloba var. treculii
3 Pappi of 5–10 lanceolate to muticous scales, all ± erose or 1–3, 1-aristate Thymophylla tenuiloba var. texana