2. Pyrrhopappus pauciflorus (D. Don) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 144. 1838.
Chondrilla pauciflora D. Don, Trans. Linn. Soc. London 16: 180. 1830; Pyrrhopappus geiseri Shinners; P. multicaulis de Candolle; P. multicaulis var. geiseri (Shinners) Northington
Annuals (sometimes persisting), 5–40(–80+) cm. Stems seldom, if ever, scapiform, branching from bases and/or distally, usually sparsely to densely pilosulous proximally, sometimes glabrous. Cauline leaves 1–3(–5+), proximal mostly oblanceolate to lance-olate, margins usually pinnately lobed, sometimes dentate or entire, distal ± lanceolate, margins usually pinnately (3–)5–7(–9+)-lobed. Heads (1–)3–7+ in loose, corymbiform arrays. Calyculi: bractlets 8–13 in 1–2 series, deltate to subulate, 3–5(–6) mm. Involucres ± campanulate to cylindric, 16–22 mm. Phyllaries 13–21. Florets 50–60; anthers 3.5 mm (pollen equatorial diameters 43–46 µm). Cypselae: bodies reddish brown, 4–5 mm, beaks 7–9 mm; pappi 7–9(–10) mm. 2n = 12.
Flowering (Feb–)Apr–May. Disturbed sites, prairies, clay soils; 10–500 m; Tex.; Mexico (Coahuila, Nuevo León, Tamaulipas).
Some specimens of Pyrrhopappus from the Panhandle of Texas and from New Mexico are intermediate for traits used here to distinguish P. pauciflorus and P. rothrockii. Some authors (e.g., B. L. Turner and K. J. Kim 1990) have included P. rothrockii within P. pauciflorus.