Difference between revisions of "Townsendia"
Fl. Bor.-Amer. 2: 16, plate 119. 1834.
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Revision as of 18:43, 24 September 2019
Annuals, biennials, or perennials, 1–2(–3) or (1–)5–15(–75+) cm (usually taprooted or developing ± woody caudices, sometimes rhizomatous). Stems decumbent to erect, branched from bases and/or distally, glabrate, glabrous, hispidulous, pilose, piloso-hirsute, piloso-strigose, scabrellous, sericeous, strigillose, strigoso-scabrellous, strigose, or villous. Leaves basal and/or cauline; alternate; ± petiolate (petioles grading into blades); blades 1-nerved, mostly spatulate to oblanceolate, lanceolate, or linear, margins usually entire, rarely toothed or lobed, faces glabrous, glabrate, pilose, scabrellous, sericeous, strigose, strigillose, or villous, abaxial often gland-dotted. Heads radiate, borne singly (± sessile among rosette leaves, or at ends of leafy stems, or on scapiform peduncles). Involucres campanulate to hemispheric or broader, 4–25(–35+) mm diam. Phyllaries persistent, (16–)20–60(–80+) in [2–]3–7+ series, 1-nerved (± flat, not notably keeled), usually ± lanceolate or ovate, sometimes filiform, lance-linear, lance-ovate, linear, obovate, oblanceolate, or subulate, unequal (outer shorter), herbaceous, margins ± scarious (often finely erose to fimbrillate), abaxial faces usually strigose to strigillose, sometimes glabrate, glabrous, glandular-puberulent, piloso-strigose, pilose, or villous. Receptacles usually flat or convex (conic in T. formosa), smooth or pitted (hairy or glabrous), epaleate. Ray florets (4–)13–34(–67+), pistillate, fertile; corollas usually white, pink, bluish, or lavender (yellow in T. aprica). Disc florets (16–)30–100(–200+), bisexual, fertile; corollas yellow (sometimes tinged with cyan), tubes shorter than cylindro-funnelform throats, lobes 5, usually erect, sometimes spreading, lance-deltate to lance-oblong; style-branch appendages lance-deltate to attenuate. Cypselae (± stramineous) ± flattened, obovate to oblanceolate, 2(–3)-nerved, faces glabrate or hairy (hair tips entire, forked, or glochidiform); pappi persistent or readily falling, of 12–35+, ± lanceolate or subulate to setiform scales (= flattened bristles of some authors; often less well developed on ray cypselae). x = 9.
Distribution
w North America, Mexico.
Discussion
Species ca. 27 (26 in the flora).
J. H. Beaman (1957) noted that apomixis (asexual production of seeds) is characteristic of some townsendias. Apomictic populations may be locally or regionally fairly uniform and differ from other apomictic populations or population systems within single taxonomic species. Consequently, the evolutionary history within Townsendia and the species concepts used in the taxonomy of Townsendia may differ from those encountered in genera that do not include apomictic plants. Hybrids between sexual plants may be perpetuated as apomicts.
Taxonomic disposition of Townsendia beamanii S. L. Welsh is not clear; the type may have resulted from hybridization between T. annua and T. incana.
Petioles and blades of townsendias intergrade; leaf descriptions and measurements here include petioles plus blades. Ratios of lengths to widths of phyllaries are expressed as “l/w = 2.5–5,” etc.
Selected References
Lower Taxa
Key
| 1 | Stems ± villous; pappi readily falling | > 2 |
| 1 | Stems usually hispidulous, scabrellous, strigose, or strigillose, sometimes glabrate or hirsute, pilose, piloso-hirsute, piloso-strigose, or strigoso-scabrellous, rarely glabrous; pappi persistent | > 4 |
| 2 | Involucres (12–)16–30 mm diam.; phyllaries 45–60+ in 5+ series, the longer 9–11 mm | Townsendia condensata |
| 2 | Involucres 4–12(–16) mm diam.; phyllaries 16–26+ in 3–4 series, the longer 5–8(–9) mm | > 3 |
| 3 | Involucres 6–12(–16) mm diam.; cypselae hairy; pappi 4.5–6+ mm | Townsendia spathulata |
| 3 | Involucres 4–8 mm diam.; cypselae glabrate or glabrous; pappi 3–5 mm | Townsendia microcephala |
| 4 | Annuals, biennials, or perennials, (1–)3–12(–75+) cm (seldom pulvinate, caudices seldom branched); internodes (0.1–)2–20(–35+) mm; leaves basal and cauline or mostly cauline; heads usually at tips of ± leafy stems (usually surpassed by closely subtending leaves) | > 5 |
| 4 | Perennials, mostly 1–3(–5+) cm (usually ± pulvinate, caudices usually branched; plants to 12+ cm in T. scapigera and T. smithii); internodes mostly 0.1–1(–2) mm; leaves basal and cauline; heads ± sessile (nested among rosette leaves) or on ± scapiform peduncles (5–)15–60(–120) mm | > 15 |
| 5 | Involucres (8–)12–25(–35+) mm diam.; phyllaries (30–)40–60(–80+) in 4–7+ series | > 6 |
| 5 | Involucres 3–20(–30) mm diam.; phyllaries 16–30(–40+) in 3–4(–5) series | > 10 |
| 6 | Leaf faces usually ± strigose, sometimes glabrate, abaxially (phyllary apices acute to attenuate, soft, not hard and apiculate) | > 7 |
| 6 | Leaf faces usually glabrous or glabrate (sometimes sparsely strigillose) abaxially (sometimes strigoso-ciliate on margins and midribs); phyllary apices often hard, ± apiculate | > 8 |
| 7 | Longer phyllaries 5–9+ mm; disc florets 80–120+; ray pappi 0.5–0.8(–2+) mm | Townsendia texensis |
| 7 | Longer phyllaries 10–15+ mm; disc florets 150–200+; ray pappi 3.5–4 (–7.5) mm | Townsendia parryi |
| 8 | Cypselae glabrous or stipitate-glandular (hair tips not forked or glochidiform) | Townsendia formosa |
| 8 | Cypselae hairy (hair tips forked or glochidiform) | > 9 |
| 9 | Phyllaries (30–)60–80+, (7–)12–13+ mm; disc pappi 8–12+, lanceolate scales 0.5–1 mm plus 1–2+, subulate to setiform scales 1–4 mm | Townsendia eximia |
| 9 | Phyllaries 30–40+, 8–10(–12+) mm; disc pappi 15–30, subulate to setiform scales (4–)5–6 mm | Townsendia grandiflora |
| 10 | Annuals; disc pappi 1–2.5(–4) mm | Townsendia annua |
| 10 | Biennials or perennials; disc pappi (2.5–)4–7+ mm | > 11 |
| 11 | Cypselae: hair tips entire or forked | Townsendia florifer |
| 11 | Cypselae: hair tips glochidiform | > 12 |
| 12 | Perennials; internodes densely hispidulous, piloso-hirsute, piloso-strigose, or strigoso-scabrellous (stem surfaces usually hidden by hairs) | > 13 |
| 12 | Biennials or perennials; internodes pilose, piloso-strigose, strigose, or strigillose (stem surfaces seldom hidden by hairs) | > 14 |
| 13 | Ray laminae 5–8(–12+) mm; disc pappi of 15–30+ scales 4–6+ mm | Townsendia incana |
| 13 | Ray laminae 3–5+ mm; disc pappi of 12–15+ scales 2.5–3+ mm | Townsendia gypsophila |
| 14 | Perennials; leaves narrowly oblanceolate to linear, 1–2(–3.5) mm wide; disc corollas 2–3.5+ mm | Townsendia fendleri |
| 14 | Biennials; leaves spatulate to oblanceolate or linear, 2–7(–9) mm wide; disc corollas 3.5–5 mm | Townsendia strigosa |
| 15 | Longer phyllaries narrowly lanceolate, lance-linear, linear, or subulate (l/w = 5–9+) | > 16 |
| 15 | Longer phyllaries usually ± lanceolate, sometimes lance-ovate, obovate, oblanceolate, or ovate (l/w = 2.5–5) | > 18 |
| 16 | Involucres (10–)12–25+ mm diam.; longer phyllaries (10–)12–14(–17) mm; disc corollas 6.5–9(–12+) mm; disc pappi 6.5–11+ mm | Townsendia exscapa |
| 16 | Involucres 7–12(–20+) mm diam.; longer phyllaries 6–9(–13) mm; disc corollas 3.5–6+ mm; disc pappi 4–6(–7.5)+ mm | > 17 |
| 17 | Involucres 8–18+ mm diam.; longer phyllaries 7–11(–13) mm; ray laminae 8–12+ mm, glabrous abaxially | Townsendia hookeri |
| 17 | Involucres 7–10 mm diam.; longer phyllaries 6–8+ mm; ray laminae 4–8+ mm, glandular-puberulent abaxially | Townsendia mensana |
| 18 | Ray laminae usually ± densely glandular-puberulent abaxially (sometimes glabrous in T. montana) | > 19 |
| 18 | Ray laminae usually glabrous, sometimes sparsely glandular-puberulent, abaxially | > 22 |
| 19 | Ray corollas yellow adaxially | Townsendia aprica |
| 19 | Ray corollas usually white, sometimes pink or blue, adaxially | > 20 |
| 20 | Longer phyllaries (7–)9–13 mm, abaxially piloso-strigose to strigose; ray florets 18–35 | Townsendia scapigera |
| 20 | Longer phyllaries 4–9 mm, abaxially glabrous, glabrate, or sparsely strigillose; ray florets 13–21+ | > 21 |
| 21 | Heads usually on scapiform peduncles 5–60+ mm, sometimes sessile; cypselae 4.5 mm | Townsendia montana |
| 21 | Heads usually sessile, sometimes on scapiform peduncles 5–15+ mm; cypselae 2–3(–4+) mm | Townsendia jonesii |
| 22 | Cypselae hairy (hair tips entire or forked) | > 23 |
| 22 | Cypselae glabrous or sparsely hairy (hairs mostly at bases, hair tips glochidiform) | > 24 |
| 23 | Heads ± sessile; pappi 3–5 mm | Townsendia minima |
| 23 | Heads on scapiform peduncles 30–80(–120) mm; pappi 0.2–0.8 mm | Townsendia smithii |
| 24 | Involucres 12–28+ mm diam.; longer phyllaries obovate to oblanceolate | Townsendia rothrockii |
| 24 | Involucres 8–12(–24) mm diam.; longer phyllaries ± lanceolate | > 25 |
| 25 | Heads usually on scapiform peduncles 10–20(–70) mm, rarely ± sessile; phyllaries 20–28+ in 3–4+ series, 5–9 mm | Townsendia glabella |
| 25 | Heads usually sessile, rarely on scapiform peduncles 5–15+ mm; phyllaries 40–50+ in 4+ series, 7–9(–12) mm | Townsendia leptotes |