Pectis cylindrica |
Asteraceae tribe Heliantheae subtribe Pectidinae |
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Sonoran chinchweed, Sonoran cinchweed, Sonoran lemonweed, three-ray chinchweed |
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Habit | Annuals, 1–20 cm (across or high); herbage not scented. | Annuals, perennials, subshrubs, or shrubs, (1–)5–50(–120+)[200+] cm. | ||||||||||||||||||||||||||||||||
Stems | prostrate to ascending (often mat-forming, densely leafy distally), puberulent (in decurrent lines or throughout) or glabrate. |
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Leaves | (bluish green) linear to linear-oblanceolate or narrowly oblong, 10–30 × 1.5–4 mm, margins with 2–5 pairs of setae 1–2 mm, faces glabrous (abaxial densely dotted with scattered, circular oil-glands 0.05–0.2 mm). |
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 | 1–5 mm. |
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Involucres | cylindric. |
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 | 3(–4); corollas 3–4 mm (scarcely surpassing phyllaries). |
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 | (3–)7–14; corollas 2.2–2.6 mm (2-lipped). |
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 | coherent (falling together), oblong to oblong-obovate, 6–10 × 2–3 mm (dotted with scattered, elliptic oil-glands 0.05–0.15 mm). |
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 | borne singly or in congested, (leafy) cymiform arrays. |
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 | 4–5.5 mm, puberulent (distally glandular-puberulent); pappi of 2 (ray) and 5 (disc) lanceolate scales 1.5–3.5 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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2n | = 48. |
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Pectis cylindrica |
Asteraceae tribe Heliantheae subtribe Pectidinae |
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Phenology | Flowering Jul–Nov. | |||||||||||||||||||||||||||||||||
Habitat | Deserts, oak-juniper woodlands, grasslands, wash channels, mud flats, lawns, roadsides | |||||||||||||||||||||||||||||||||
Elevation | 700–1500 m (2300–4900 ft) | |||||||||||||||||||||||||||||||||
Distribution |
AZ; NM; TX; Mexico (Baja California Sur, Chihuahua, Coahuila, Durango, Nuevo León, Sinaloa, Sonora)
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Mostly subtropical; tropical; and warm-temperate; especially arid New World |
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Discussion | Pectis cylindrica (2n = 48) is similar to P. prostrata (2n = 24); the two occasionally grow together (D. J. Keil 1975b). Some herbaria contain mixed collections of the two. No evidence is available of hybrids between the two. (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. 225. | FNA vol. 21, p. 221. | ||||||||||||||||||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis | Asteraceae > tribe Heliantheae | ||||||||||||||||||||||||||||||||
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Synonyms | P. prostrata var. cylindrica | subtribe Tageteae | ||||||||||||||||||||||||||||||||
Name authority | (Fernald) Rydberg: in N. L. Britton et al., N. Amer. Fl. 34: 198. (1916) | Lessing: Linnaea 5: 134. (1830) | ||||||||||||||||||||||||||||||||
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