Pectis angustifolia var. tenella |
Asteraceae tribe Heliantheae subtribe Pectidinae |
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lemonscent, low pectis, Mexican chinchweed |
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Habit | Annuals, 2–15 cm; herbage spicy-scented (lemon-scented in some Mexican populations). | Annuals, perennials, subshrubs, or shrubs, (1–)5–50(–120+)[200+] cm. | ||||||||||||||||||||||||||||||||
Leaves | 10–40 mm, bases of distal blades not notably expanded. |
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 | 5–15 mm. |
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Involucres | 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 | 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 | 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 | linear, 3–5 mm, widest near middles, each with 1 subterminal oil-gland 0.2–0.5 mm plus smaller, submarginal oil-glands. |
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 | 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 | 2.5–4 mm; pappi of 0–7 awns or bristles 1–3 mm and/or coroniform. |
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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2n | = 24. |
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Pectis angustifolia var. tenella |
Asteraceae tribe Heliantheae subtribe Pectidinae |
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Phenology | Flowering Jun–Dec. | |||||||||||||||||||||||||||||||||
Habitat | Deserts, grasslands, arid woodlands, shrublands, roadsides | |||||||||||||||||||||||||||||||||
Elevation | 100–1100(–2500) m (300–3600(–8200) ft) | |||||||||||||||||||||||||||||||||
Distribution |
NM; TX; Mexico (Aguascalientes, Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Tamaulipas, Veracruz, Zacatecas) |
Mostly subtropical; tropical; and warm-temperate; especially arid New World |
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Discussion | Variety tenella is widely distributed in the Chihuahuan Desert and adjacent regions. The isolated occurrence in northern New Mexico perhaps represents an introduction. (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. 229. | FNA vol. 21, p. 221. | ||||||||||||||||||||||||||||||||
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Synonyms | P. tenella | subtribe Tageteae | ||||||||||||||||||||||||||||||||
Name authority | (de Candolle) D. J. Keil: Rhodora 79: 58. (1977) | Lessing: Linnaea 5: 134. (1830) | ||||||||||||||||||||||||||||||||
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