Thymophylla tenuiloba |
Asteraceae tribe Heliantheae subtribe Pectidinae |
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bristleleaf pricklyleaf, Dahlburg-daisy, shooting star |
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Habit | Annuals (rarely persisting), green, to 30 cm, glabrous or sparsely hirtellous. | Annuals, perennials, subshrubs, or shrubs, (1–)5–50(–120+)[200+] cm. | ||||||||||||||||||||||||||||||||||||||||||||
Stems | decumbent to erect. |
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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). |
mostly cauline, sometimes basal or basal and cauline; mostly opposite (distal sometimes alternate) or mostly alternate; petiolate or sessile; blades usually elliptic, filiform, lanceolate, linear, or ovate, often 1(–2)-pinnately lobed, ultimate margins entire or toothed (often proximally bristly-ciliate), faces glabrous or puberulent to tomentose (usually bearing oil-glands, embedded pellucid glands filled with strong-scented, essential oils). |
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Peduncles | 30–80 mm, glabrous or hirtellous. |
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Involucres | obconic, 5–7 mm. |
campanulate, cylindric, hemispheric, obconic, or turbinate. |
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Receptacles | flat or convex to hemispheric or conic, epaleate (receptacles sometimes pitted, pit margins sometimes fimbrillate to laciniate). |
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Ray florets | 10–21; corollas yellow-orange, laminae 4–10 × 1.5–3 mm. |
0 or 1–21+, pistillate, fertile; corollas yellow to orange (sometimes with brown or mostly brown) or white to pink, magenta, or reddish purple. |
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Disc florets | 50–100+; corollas yellow, 2.5–4.5 mm (peripheral ± zygomorphic in some plants). |
1–120+, usually bisexual and fertile [functionally staminate]; corollas yellow to orange or brown, or pinkish to purplish or reddish, tubes much shorter than to much longer than cylindric to funnelform throats, lobes 5, deltate to lance-linear (equal or unequal); anther thecae pale or ± darkened; stigmatic papillae in 2 lines. |
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Phyllaries | 12–22, margins of outer distinct less than 1/5 their lengths, abaxial faces glabrous or sparsely hirtellous. |
falling or persistent, 3–21+ in 1–2 series (distinct or ± connate, mostly linear to lanceolate, usually subequal, usually some or all bearing pellucid oil-glands as in leaves). |
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Calyculi | of 3–8 deltate to subulate bractlets, lengths less than 1/2 phyllaries. |
0 or of 1–22 bractlets. |
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Heads | radiate or discoid (sometimes radiant, e.g., in Thymophylla), usually borne singly, sometimes in loose to crowded, corymbiform or cymiform arrays. |
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Cypselae | 2–3.5 mm; pappi of erose and/or aristate scales 0.7–3.5 mm. |
mostly clavate to obpyramidal (lengths usually 2–3+ times diams.), glabrous or hairy; pappi usually persistent, of 20–50 bristles in 1–2+ series, or of 5–20 (sometimes aristate) scales in 1–2 series, or combinations of bristles and scales in 1–2+ series, rarely coroniform or 0. |
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Thymophylla tenuiloba |
Asteraceae tribe Heliantheae subtribe Pectidinae |
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Distribution |
TX; n Mexico
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Mostly subtropical; tropical; and warm-temperate; especially arid New World |
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Discussion | Varieties 4 (4 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 22, species 225 (9 genera, 38 species in the flora). Circumscription of Pectidinae has been fairly constant for decades. The group is sometimes given tribal rank, as Tageteae. Here, we have followed H. Robinson (1981). The group is usually distinguished on the basis of schizogenous glands containing essential oils (mostly terpenes) in tissues of leaves and/or phyllaries (sometimes in tissues of other organs as well). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 242. | FNA vol. 21, p. 221. | ||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Thymophylla | Asteraceae > tribe Heliantheae | ||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Hymenatherum tenuilobum, Dyssodia tenuiloba | subtribe Tageteae | ||||||||||||||||||||||||||||||||||||||||||||
Name authority | (de Candolle) Small: Fl. S.E. U.S., 1295, 1341. (1903) | Lessing: Linnaea 5: 134. (1830) | ||||||||||||||||||||||||||||||||||||||||||||
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