Pyrrhopappus
in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 144. 1838.
Annuals or perennials, 5–100+ cm; taprooted or rhizomatous (roots producing tuberiform swellings in P. grandiflorus). Stems usually 1, sometimes 2–5+, erect, unbranched or branched proximally and/or distally, glabrous or pilosulous. Leaves basal or basal and cauline; basal ± petiolate, distal usually sessile; blades oblong, elliptic, or ovate to lanceolate or linear, margins entire or dentate to pinnately lobed (faces usually glabrous, sometimes pilosulous near margins). Heads borne singly or in loose, corymbiform arrays. Peduncles not inflated distally, sometimes bracteate. Calyculi of 3–13+, deltate to subulate or filiform bractlets. Involucres cylindric, 4–5[–8+] mm diam. Phyllaries 8–21+ in ± 2 series (reflexed in fruit), linear, equal, margins often scarious, apices acute (often thickened or bearing keel-like flaps near tips). Receptacles ± convex, pitted, glabrous, epaleate. Florets (20–)30–150+; corollas yellow to whitish. Cypselae reddish brown to stramineous, bodies ± fusiform, beaks (± concolorous with bodies) ± filiform, fragile, grooves (or broad ribs) 5, faces transversely rugulose, glabrous; pappi (borne on discs at tips of beaks) persistent, double: outer coroniform (of whitish, relatively short, spreading, sometimes curly, hairs), inner of 80–120+, rufous to stramineous, subequal, barbellulate bristles in 2–3+ series. x = 6.
Distribution
North America, Mexico.
Discussion
Species 1, 4, or 5 (4 in the flora).
Some plants from Mexico that have been called Pyrrhopappus multicaulis de Candolle (type from Mexico) may be distinct at species rank from P. pauciflorus (see R. McVaugh 1984).
Almost all botanists who have dealt with the biology or floristics of pyrrhopappuses have remarked similarities among the taxa and/or difficulties with identification of some specimens. Some botanists have noted that “interspecific” hybridizations are common (D. K. Northington 1974; B. L. Turner and K. J. Kim 1990; and works cited therein).
Selected References
Lower Taxa
Key
| 1 | Perennials (roots or rootstocks producing tuberiform swellings 1–15 cm below soil surface); stems usually scapiform; cauline leaves usually 0, sometimes 1–3; anthers 4.5–5 mm. | Pyrrhopappus grandiflorus |
| 1 | Annuals or perennials (not producing tuberiform swellings); stems rarely scapiform; cauline leaves usually 3–9+, seldom 0–2; anthers 2.5–4 mm | > 2 |
| 2 | Stems usually sparsely to densely pilosulous proximally, sometimes glabrous; blades of distal cauline leaves usually pinnately (3–)5–7(–9+)-lobed | Pyrrhopappus pauciflorus |
| 2 | Stems usually glabrous proximally, sometimes pilosulous; blades of distal cauline leaves usually entire or with 1–2 lobes near bases, sometimes pinnately 3–5(–7+)-lobed | > 3 |
| 3 | Perennials; involucres 12–15(–17+) mm; florets 30–60+; cypselae stramineous; pappi 6–7 mm | Pyrrhopappus rothrockii |
| 3 | Annuals; involucres 17–24 mm; florets 50–150+; cypselae reddish brown; pappi 9–10 mm | Pyrrhopappus carolinianus |