Pectis cylindrica |
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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. |
Stems | prostrate to ascending (often mat-forming, densely leafy distally), puberulent (in decurrent lines or throughout) or glabrate. |
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). |
Peduncles | 1–5 mm. |
Involucres | cylindric. |
Ray florets | 3(–4); corollas 3–4 mm (scarcely surpassing phyllaries). |
Disc florets | (3–)7–14; corollas 2.2–2.6 mm (2-lipped). |
Phyllaries | coherent (falling together), oblong to oblong-obovate, 6–10 × 2–3 mm (dotted with scattered, elliptic oil-glands 0.05–0.15 mm). |
Heads | borne singly or in congested, (leafy) cymiform arrays. |
Cypselae | 4–5.5 mm, puberulent (distally glandular-puberulent); pappi of 2 (ray) and 5 (disc) lanceolate scales 1.5–3.5 mm. |
2n | = 48. |
Pectis cylindrica |
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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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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.) |
Source | FNA vol. 21, p. 225. |
Parent taxa | |
Sibling taxa | |
Synonyms | P. prostrata var. cylindrica |
Name authority | (Fernald) Rydberg: in N. L. Britton et al., N. Amer. Fl. 34: 198. (1916) |
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